











03 0 ^ V 'As 

. <•> 


c. z 

; V> ^ o 

' ^ K >9 - » 

^ V * ^ £> -4 

. , fi ^ y n .i * A 

O 0 Aw??^A A 

- ^ K 

: v <o o * 

* ^ 
C> *• 

« « ,. -v -3 N 0 - o - o a 

0 - .’••f t 

53 . 53 ^ 'P 

* 'v A ct- a/x'S&^ta, ^ 

^ c> 




\ ' o n <; * ^ ^ * * * s S ^ 

A A ?-, ,A’ v 



V> ^ - WM ^ 
a ^ v ^ aaA 

f v ( on.^ tA \. i it c Y 0 * A A 

• - ' ^ o°VlU^ ^ # x c» 


* v 


rj> ^ ^ ->A J 

A 3 f* 0 'A 



. * K 

°o, »« 

^*a o. \K s LZ! 



& y V 

\ . A> V \Vj*v£ w**wc \r-££ >, 

* * * A o A s s < 6 V 

A \sJ V A> ,0> a v * A ^ 



. > t ^ <y S ” ( 

. ^ 0 N c . 1 it * ^ ** 

'O * ^C\- rO V V 

^> v < 2 > * 

* * f ^ > 

'V ^ 



♦ A' 

9 - <r *> S . 1 a 

C- ±ae/r??^ ^ + 


s'%A '"' - J A€ 
c o^v«' 7 */A 

* '- <* a n 

^ ■* ^ v 


















































• V 


* K 


A 



C; 



V » B 


A V ^ * 

<0 'V / ~ . s V G 

A ^ <^\\ />%, ^ . * 4t'(i!//Y^ + -r - iN 

1 « *oCr 

* 4 v* 

v 

©,. *,, A.4-:.»',.o 




... -.O' \» r ,„, V»»»’'/ * « 0 »' .* 

*"/• % v > A 0‘ ^ Vft °/- C‘ * X 

° Ap .<V ^ /'^iffiife^ - ca> 



jV * ^ 



\>V\;;> 

, "o %j. ,<^’ «J 8 | 


5 0 


,\ 



-v J <^ * 

^ \ n ■%"" 

^ * A. V» N = 

/& -< ^ > * 

^ * 


: x° v* t 


^ - 
*. %A 

^ T> « 







A 



• A 4 - 

^ «> \', . o 

, s * <L> rO i, ^ \v) _ . 

o 1,1 v' ,'”' 4 ^ aK<, A 0 ^ »•'"», 4 

* 'p ^ y a A 


o 


7 s 


* - 

z - ^ 
"'C^ o 

> * * 
C ° N c <. C? r 0’ <A ' % V 

^. o> L> ^ ^AAh-, 



4 


> <A 




</>- n 

■ >> * 

-4 ✓ 

* A X „ N r 'V *•* *'* ' S ^ v 1 

aA C AL % °~ * 



^: 


0 IM o 



•"o o* 
o5 ^ * 

\ »in* \V , * * , ^ 

0 Z' o V s 

: A * *P K 

^A, ^ V' <V; ^ 

4 ° 4 - 

^ *_r -, , s, . . . v- x 

(i /> A * aV </> 

v / 4 ■# % V 

^ ^ v * . -A A <$ 'V J 

(\V «■ - - - ilf A -0 t - 'T O. 

'J v ^ ^c» f ^> x> <-^\\ • O 

•< ^ V c 

^ <* 



x\ 




% A \ > * 

V 3 O .A c 


v\ 





0 o 


\ ^' f s^ r'S.' j U JF 1 

' *»/v*• "' , ~° ^ 


^ a"^’ ^ ^ ^ 


(.■f 0 «'-'** 

0 ° jV^.% ^ 


\°°< 




-X «A> ^ 

^ A, O ^ . - s 

/ c 0 C « x O- r 


o va . 

/. ; 

O <A <A 

^ oV 

% , 0 V <,**o\\+ \ A 

o ? ,«'"*% a ,#,<: 

xS ^/r. > f ^ A \ ^ c-s: 










































































LOCOMOBILE “38” SIX-PASSENGER TOURING CAR 

Courtesy of the Locomobile Company of America, Bridgeport, Connecticut 










Cyclopedia 

of 

Automobile Engineering 


A General Reference JVork on 

THE CONSTRUCTION, OPERATION, CARE AND REPAIR OF GASOLINE, ELECTRIC, 
AND STEAM AUTOMOBILES, COMMERCIAL VEHICLES, MOTORCYCLES, 

AND MOTOR BOATS; IGNITION, STARTING, AND LIGHTING 
SYSTEMS; EXPLOSION MOTORS; DRIVING; 

TROUBLES; GARAGES; REPAIRS; WELDING 


Prepared by a Staff ' of 

AUTOMOBILE EXPERTS, CONSULTING ENGINEERS, AND DESIGNERS OF THE 

HIGHEST PROFESSIONAL STANDING 


Illustrated with over Fifteen Hundred Engravings 


FIVE VOLUMES 



CHICAGO 

AMERICAN TECHNICAL SOCIETY 

1916 



TL !4b 

,6 



COPYRIGHT, 1909, 1910, 1912, 1915, 1916 

BY 

AMERICAN TECHNICAL SOCIETY 


Copyrighted in Great Britain 
All Rights Reserved 





7 / / 7 

MIR 30 I9'6 

©CI.A427471 

. t 


\ 



Authors and Collaborators 


CHARLES B. HAYWARD 

Member, Society of Automobile Engineers 
Member, The Aeronautical Society 

Formerly Secretary, Society of Automobile Engineers 
Formerly Engineering Editor, The Automobile 


C. T. ZIEGLER 

Automobile Engineer 

Formerly Manager, The Ziegler Company, Chicago 
With Inter-State Motor Company, Muncie, Indiana 


V* 

MORRIS A. HALL, B. S. 

Formerly Managing Editor, Motor Life 

Editor, The Commercial Vehicle; Editor, The Automobile Journal, Motor Truck, etc. 
Author of “What Every Automobile Owner Should Know”; “Motorist’s First Aid Hand¬ 
book”, etc. 

Formerly Associate Editor, The Automobile 
Member, Society of Automobile Engineers 
Member, American Society of Mechanical Engineers 


V* 

HUGO DIEMER, M. E. 

Professor of Industrial Engineering, Pennsylvania State College 
American Society of Mechanical Engineers 


DARWIN S. HATCH, B. S. 

Associate Editor, Motor Age, Chicago 
Formerly Managing Editor, The Light Car 
Member, Society of Automobile Engineers 
American Automobile Association 




GLENN M. HOBBS, Ph. D. 

Secretary and Educational Director, American School of Correspondence 
Formerly Instructor in Physics, The University of Chicago 
American Physical Society 


V* 

CHARLES H. HUGHES 


Naval Architect and Marine Engineer 



Authors and Collaborators—Continued 


HERBERT LADD TOWLE, B. A. 

Specialist in Technical Advertising 
Member, Society of Automobile Engineers 
Formerly Associate Editor, The Automobile 




GEORGE W. CRAVENS 

Mechanical and Electrical Engineer 

Sales Manager, C and C Electric & Manufacturing Company 

EDMOND M. SIMON, B. S. 

Superintendent Union Malleable Iron Company, East Moline, Illinois 


EDWARD B. WAITE 

Dean and Head, Consulting Department, American School of Correspondence 
Member, American Society of Mechanical Engineers 


HAROLD W. ROBBINS,*M. E. 

Formerly Instructor, Lewis Institute, and Armour Institute, Chicago 
Special Writer and Technical Investigator 

F. HALLETT LOVELL, Jr. 

President and Treasurer, Lovell-McConnell Manufacturing Company 




W. R. HOWELL 

President, W. R. Howell and Company, London, England 


ERNEST L. WALLACE, B. S. 

Assistant Examiner, United States Patent Office, Washington, D. C. 
American Institute of Electrical Engineers 

V * 


JESSIE M. SHEPHERD, A. B. 

Head, Publication Department, American Technical Society 



Authorities Consulted 


T HE editors have freely consulted the standard technical literature 
of America and Europe in the preparation of these volumes. They 
desire to express their indebtedness, particularly, to the following 
eminent authorities, whose well-known treatises should be in the library 
of everyone interested in the Automobile and allied subjects. 

Grateful acknowledgment is here made also for the invaluable co-oper¬ 
ation of the foremost Automobile Firms and Manufacturers in making these 
volumes thoroughly representative of the very latest and best practice in 
the design, construction, and operation of Automobiles, Commercial Vehi¬ 
cles, Motorcycles, Motor Boats, etc.; also for the valuable drawings, data, 
illustrations, suggestions, criticisms, and other courtesies. 


CHARLES E. DURYEA 

Consulting Engineer 

First Vice-President, American Motor League 
Author of “Roadside Troubles” 

V- 

OCTAVE CHANUTE 

Late Consulting Engineer 

Past President of the American Society of Civil Engineers 
Author of “Artificial Flight,” etc. 

V* 


E. W. ROBERTS, M. E. 

Member, American Society of Mechanical Engineers 

Author of “Gas-Engine Handbook,” “Gas Engines and Their Troubles,” “The Auto¬ 
mobile Pocket-Book,” etc. 

V 

SANFORD A. MOSS, M. S., Ph. D. 

Member, American Society of Mechanical Engineers 
Engineer, General Electric Company 
Author of “Elements of Gas Engine Design” 

*y 

GARDNER D. HISCOX, M. E. 

Author of “Horseless Vehicles, Automobiles, and Motorcycles,” “Gas, Gasoline, and 
Oil Engines,” “Mechanical Movements, Powers, and Devices,” etc. 

AUGUSTUS TREADWELL, Jr., E. E. 

Associate Member, American Institute of Electrical Engineers 

Author of “The Storage Battery: A Practical Treatise on the Construction, Theory, and 
Use of Secondary Batteries” 




Authorities Consulted—Continued 


BENJAMIN R. TILLSON 

Director, H. J. Willard Company Automobile School 
Author of “The Complete Automobile Instructor” 

THOMAS H. RUSSELL, M. E., LL. B. 

Editor, The American Cyclopedia of the Automobile 

Author of ‘ Motor Boats,” “History of the Automobile,” “Automobile Driving, Self- 
Taught,” “Automobile Motors and Mechanism,” “Ignition Timing and Valve Set¬ 
ting,” etc. 

V* 

CHARLES EDWARD LUCRE, Ph. D. 

Mechanical Engineering Department, Columbia University 
Author of “Gas Engine Design” 

V* 

P. M. HELDT 

Editor, Horseless Age 

Author of “The Gasoline Automobile” 

V» 

H. DIEDERICHS, M. E. 

Professor of Experimental Engineering, Sibley College, Cornell University 
Author of “Internal Combustion Engines” 

V 


JOHN HENRY KNIGHT 

Author of “Light Motor Cars and Voiturettes,” “Motor Repairing for Amateurs,” etc. 


WM. ROBINSON, M. E. 

Professor of Mechanical and Electrical Engineering in University College, Nottingham 
Author of “Gas and Petroleum Engines” 

V* 


W. POYNTER ADAMS 

Member, Institution of Automobile Engineers 
Author of “Motor-Car Mechanisms and Management” 

V* 

ROLLA C. CARPENTER, M. M. E., LL. D. 

Professor of Experimental Engineering, Sibley College, Cornell University 
Author of “Internal Combustion Engines” 

V- 


ROGER B. WHITMAN 

Technical Director, The New York School of Automobile Engineers 
Author of “Motor-Car Principles” 



Authorities Consulted—Continued 


CHARLES P. ROOT 

Formerly Editor, Motor Age 

Author of “Automobile Troubles, and How to Remedy Them” 

V* 

W. HILBERT 

Associate Member, Institute of Electrical Engineers 
Author of “Electric Ignition for Motor Vehicles” 

V* 


SIR HIRAM MAXIM 

Member, American Society of Civil Engineers 
British Association for the Advancement of Science 
Chevalier Legion d’Honneur 
Author of “Artificial and Natural Flight,” etc. 


SIGMUND KRAUSZ 

Author of “Complete Automobile Record,” “A B C of Motoring” 




JOHN GEDDES McINTOSH 

Lecturer on Manufacture and Application 
Institute, London 

Author of “Industrial Alcohol,” etc. 


of Industrial Alcohol, at the Polytechnic 


FREDERICK GROVER, A. M., Inst. C. E., M. I. Mech. E. 

Consulting Engineer 

Author of “Modern Gas and Oil Engines” 

V* 

FRANCIS B. CROCKER, M. E., Ph. D. 

Head of Department of Electrical Engineering, Columbia University 
Past President, American Institute of Electrical Engineers 

Author of “Electric Lighting;” Joint Author of “Management of Electrical Machinery” 


V* 


A. HILDEBRANDT 

Captain and Instructor in the Prussian Aeronautic Corps 
Author of “Airships Past and Present” 


T. HYLER WHITE 

Associate Member, Institute of Mechanical Engineers 
Author of “Petrol Motors and Motor Cars” 



Authorities Consulted—Continued 


ROBERT H. THURSTON, C. E., Ph. B., A. M., LL. D. 

Director of Sibley College, Cornell University 

Author of “Manual of the Steam Engine,” “Manual of Steam Boilers,” etc. 


V* 

MAX PEMBERTON 

Motoring Editor, The London Sphere 
Author of “The Amateur Motorist” 


HERMAN W. L. MOEDEBECK 

Major and Battalions Kommandeur in Badischen Fussartillerie 
Author of “Pocket-Book of Aeronautics” 


EDWARD F. MILLER 

Professor of Steam Engineering. Massachusetts Institute of Technology 
Author of “Steam Boilers” 

V» 

ALBERT L. CLOUGH 

Author of ‘ Operation, Care, and Repair of Automobiles” 


W. F. DURAND 

Author of “Motor Boats,” etc. 


V 

PAUL N. HASLUCK 

Editor, Work and Building World 
Author of “Motorcycle Building” 

JAMES E. HOMANS, A. M. 

Author of “Self-Propelled Vehicles” 


R. R. MECREDY 

Editor, The Encyclopedia of Motoring, Motor News, etc. 

V* 

S. R. BOTTONE 

Author of “Ignition Devices,” “Magnetos for Automobiles,” etc. 


V* 

LAMAR LYNDON, B. E., M. E. 

Consulting Electrical Engineer 

Associate Member, American Institute of Electrical Engineers 
Author of “Storage Battery Engineering” 




COLE COUPE WITH EIGHT-CYLINDER MOTOR 

Courtesy of Cole Motor Car Company, Indianapolis, Indiana 




























fc 

o 

H 

W 

w 

A 

x 

►H 

CO 

I 

« 

w 

ft 

p 

CO 

fe 

o 

CO 

Q 

p 

» 


Courtesy of Hudson Motor Car Company , Detroit , Michigan 




















Foreword 


W ITHIN recent years the internal-combustion motor and 
the self-propelled vehicle have become such important 
factors in the evolution of industrial, commercial, and social life, 
that a distinct need has been created for an authoritative work 
of reference on this subject. Such a work should treat of the 
results and methods of the latest approved practice in the con¬ 
struction, care, and operation of the various types of motor cars 
and other vehicles driven by gas, electricity, and steam, and of 
the allied branches of this rapidly developing field of apparently 
unlimited possibilities. It is the purpose of the Cyclopedia of 
Automobile Engineering to fill this acknowledged need. 

C. The application of the internal-combustion motor, the 
electric motor, the storage battery, and the steam engine to the 
development of types of mechanically-propelled road carriages 
and motor boats, is a far-reaching engineering problem of great 
difficulty. Nevertheless, through the aid of the best scientific 
and mechanical minds in this and other countries, every detail 
has received the amount of attention necessary to make it as 
perfect as possible. Today the automobile is a wonderfully 
reliable and efficient machine. Road troubles, except in connec¬ 
tion with tires, have become almost negligible and even the in¬ 
experienced novice, who knows barely enough to keep to the road 
and shift gears properly, can venture on long touring trips with¬ 
out fear of getting stranded. Astonishing refinements in the 
ignition, starting and lighting systems have been lately effected, 
thus adding not only to the reliability of the electrical equip- 





ment of the automobile but adding greatly to the pleasure in 
running the car. With the possibility of extending the electrical 
control to the shifting of gears and other important functions, 
the electric current assumes a much more important position in 
connection with the gasoline automobile than heretofore. Alto¬ 
gether, the automobile as a whole has become standardized and, 
unless some unforeseen developments are brought about, future 
changes in either the gasoline or the electric automobile will be 
merely along the line of greater refinement of the mechanical 
and electrical devices used. 

H Special effort has been made to emphasize the treatment of 
the Electrical Equipment of gasoline cars, not only because it is 
in this direction that most of the improvements have lately taken 
place, but also because this department of automobile construc¬ 
tion is least familiar to owners, repair men and others interested 
in the details of the automobile. A multitude of diagrams have 
been supplied showing the constructive features and wiring cir¬ 
cuits of the principal systems. In addition to this instructive 
section, much valuable information to garage and repair men 
has been included in connection with the analysis of the de¬ 
tails of the car. 

C. For purposes of ready reference and timely information so 
frequently needed in automobile operation and repair, it is 
believed that these volumes will be found to meet every re¬ 
quirement. 

C Grateful acknowledgment is due the corps of authors and 
collaborators — engineers of wide practical experience, and 
teachers of well-recognized ability—without whose co-operation 
this work would have been impossible. 


Table of Contents 


VOLUME I 

Explosion Motors . . Revised by Morris A. Hallf Page *11 

Historical—Explosion-Motor Cycle: Four-Stroke Cycle, Two-Stroke Cycle, Six- 
Stroke Cycle—Types of Explosion Motors: Automobile, Marine, Motorcycle, Aero¬ 
nautical Motors—Motor Details: Four-Cycle Type, Valves, Ignition, Lubrication, 
Cooling, Clutch, Crank and Firing Arrangements—Two-Cycle Type—Four-, Six-, 

Eight-, and Twelve-Cylinder Motors — Power — Governing — Thermodynamics: 
Indicators, Manograph, Thermal Efficiency—Otto Cycle in Practice: Suction, 
Compression, Explosion and Exhaust Strokes—Modifications for Modern Motors— 

Fuels—Horsepower and Rating Calculations 


Welding in Automobile Repair Shops By George W. Cravens Page 99 

Development of Field: Rise of Automobile Industry, Improved Methods of 
Repair—Conditions for Proper Welding: Different Metals, Fluxes, Equipment, 
Amount of Heat, Preparing Work — Welding Processes — Methods of Pre- 
Heating: Handling Different Classes of Work, Instructions for Using Forges, 
Torches, etc. — Electric Arc Welding: Process, Equipment — Gas Welding: 
Process, Method, Equipment—Welding Operations: Kinds of Repairs, Prepa¬ 
ration of Jcb, Methods of Welding, Cost Data—Strength of Welds—Time of 
Operations—Use of Welding in Automobile Manufacture 


Gasoline Automobiles ... By Morris A. Hall Page 161 

Introduction—Features of Motor-Car Construction: General Outline, Engine 
Elements, Water Cooling, Air Cooling, Carburetion, Ignition, Lubrication, Bear¬ 
ings, Transmission Elements, Running-Gear Elements, Electric Lighting and 
Starting, Body Types—Valve Gears: Cams (Friction, Valve Settings, Cam De¬ 
sign), Sliding Sleeve Valves (Gear Control, Eccentric and Lever Control, Knight 
Sleeve Valves), Rotating Valves—Carbureters: Classification, Throttle Valve, 

Needle Valves, Floats, Adjustment of Air and Gasoline Supply (Handling Fuel 
Spray, Water-Jacketing, Auxiliary Air Valve, Venturi Tube Mixing Chamber), 
Carbureter Types (Standard Practice, Double-Nozzle Type, Browne Type, Kero¬ 
sene and Heavy Fuel Types), Carbureter Troubles, Fuel Supply (Tank Placing, 
Feeding, Piping and Connections, Reserve Tanks) Clutches: Cone, Contracting 
Band, Expanding Band, Multiple Disc (Simple Type, Metal-To-Metal, Use of 
Facing), Combination Cone and Disc, Hydraulic, Magnetic, Clutch Operation, 
Lubrication, Bearings and Adjustments—Transmissions: Sliding Gears (Selective, 
Progressive, Electrically Operated, Pneumatic, Railway-Car Needs, Rear Axle 
Combinations), Individual Gears, Planetary Gears (Ford, Railway Type Without 
Reverse, Duryea, Radcliffe 3-Speed), Friction Disc, Miscellaneous Types (Cable, 
Hydraulic, Pneumatic, Electric), Types of Gears (Spur, Bevel, Herringbone, 

Spiral, and Worm Gears)—Brakes: Function, Internal Expanding, External 
Contracting, Electric Brakes 


Review Questions. Page 417 

Index. Page 425 


* For page numbers, see foot of pages. 

tFor professional standing of authors, see list of Authors and Collaborators at 
front of volume. 






OLDSMOBILE “LIGHT” EIGHT-CYLINDER MOTOR 

Courtesy of Olds Motor Works, Lansing, Michigan 


EIGHT-CYLINDER KING MOTOR, MOUNTED IN CHASSIS 

Courtesy of King Motor Car Company, Detroit, Michigan 


































EXPLOSION MOTORS 

ELEMENTARY PRINCIPLES 

General Description. The term explosion motor as herein used 
refers primarily to gasoline engines such as are used on aerial crafts, 
automobiles, motorcycles, motorboats, and small stationary instal¬ 
lations. There is nothing mysterious about this form of engine, it 
being similar in most respects to the ordinary 
steam engine, except that the force which 
develops the power is derived not from the 
expansion of steam, but from the explosion of 
a gaseous charge consisting of a mixture of oil 
vapor and air. 

The simplest type of motor, Fig. 1, consists 
primarily of a cylinder A in which there is a 
hollow piston B (free to slide up and down), a 
crank shaft C, and a rod D, connecting the 
piston through the piston pin E to the crank 
on the shaft. As the piston moves up and 
down in the cylinder this reciprocating motion 
is converted by the operation of the connecting 
rod on the crank F into a rotary motion, as 
shown by the arrow near C . The whole action 
may be compared to that of a boy on a bicycle, 

D representing the boy’s leg and F the pedal. 

At the head of the cylinder are shown two 
valves, G and H , and a spark plug I, whose functions are to admit 
the charge, explode it, and permit it to escape, by which operations 
and their repetition the reciprocating motion of the piston is set up 
and maintained. The successive explosions of the charges produce 
considerable heat and, therefore, in actual practice the cylinder A is 
usually surrounded by a jacket. Water is circulated around in the 
space between this jacket and the cylinder, thus cooling the cylinder. 
Another cooling method is by air, in which case the outer wall of the 



Fig. 1. Simple Explosion 
Motor 


11 















2 


EXPLOSION MOTORS 


cylinder is constructed as shown in Figs. 16 and 17. In order, there¬ 
fore, to secure the above action, the following mechanical devices 
must be provided: (1) A cylinder containing a freely moving piston, 
capable of being lubricated effectively; (2) a combustion chamber 
in whose walls are valves for the admission and exhaust of the gas, 
and valve seats so arranged that the joints will remain gas-tight 
when desired; (3) an outside, dependable means of ignition, with 
sparking points inside the combustion chamber; (4) a source of fuel 
supply, which, in the ordinary engine, must convert liquid into a 
vapor; and (5) a cylinder construction which will carry off the 
surplus heat or allow of its being carried off. 

Historical. The first workers in this field were perhaps 
Huyghens, Hautefeuille, and Papin, who experimented with motors 
using gunpowder as a fuel in the latter part of the seventeenth 
century. A patent was obtained in England by John Barber, in the 
closing years of the eighteenth century, on a turbine using a mixture 
of gas or vapor and air for the fuel. A few years later Robert Street, 
another Englishman, built an oil engine in which the vapor was 
ignited by a flame at the end of the first half of the outward stroke. 

From 1800 to 1854 several French and English patents were 
granted for internal combustion engines, most of the engines being 
double acting, i.e., one explosion acting on one side and the next 
explosion acting on the other side of the piston, and some using 
electrical ignition. In 1858, Degrand made a big advance by com¬ 
pressing the mixture in the cylinder instead of in separate pumps. 

First Practical Engine. The first commercially practical engine 
was developed about 1860 by Lenoir, who marketed in Paris a 
1-horse-power, double-acting gas engine closely resembling a hori¬ 
zontal steam engine. This used what is now called jump-spark 
ignition and was made in sizes up to 12 horse-power. It gave con¬ 
siderable trouble in many cases, but the principal reason for its 
failure was the excessive amount of gas required, viz, 60 to 100 cubic 
feet of illuminating gas per brake-horse-power hour,* which was 
more than three times the consumption of a modern gas engine, 
and prevented competition with steam. 

Otto Engine . The gas engine industry as we know it today was 
really started in 1861, when a young German merchant, N. A. Otto, 

*Brake horse-power (b. h p ) is the power delivered from the shaft of the encine When 
delivered for one hour it is called a b.h.p.-hour. me engine, wnen 


12 



EXPLOSION MOTORS 


3 


developed an experimental engine in which admission, compression, 
ignition, and exhaust were accomplished in the one working cylinder. 
Otto failed to realize fully the great promise held out by his engine 
and temporarily abandoned its development. 

Be Rochas’ Theory. In the year 1862 it was pointed out by 
a French engineer, Beau de Rochas, that in order to get high economy 
in a gas engine certain conditions of operation were necessary, the 
most important being that the explosive mixture shall be compressed 
to a high pressure before ignition. In order to accomplish this, he 
proposed that the cycle of operations should occupy four strokes or 
two complete revolutions of the engine and that the operation should 
be as follows: 

(1) Suction or admission of the mixture throughout the complete for¬ 
ward stroke. 

(2) Compression of the mixture during the whole of the return stroke, 
so that it finally occupies only the clearance space between the piston and 
cylinder head. 

(3) Ignition of the charge at the end of the second stroke and expansion 
of the exploded mixture throughout the whole of the next forward stroke. 

(4) Exhaust beginning at the end of the forward stroke and continuing 
throughout the whole of the last return stroke. 

De Rochas had developed a brilliant theory but never put it into 
practical use. The pamphlet containing this idea remained practically 
unknown until about 1876, when it was discovered and published in 
the course of a patent-lawsuit against Otto and his associates, who 
were using this cycle in their engine, Otto having returned to the 
development of his engine in 1863. Although the original idea was 
perhaps Beau de Rochas’, the credit really belongs to Otto, who 
made practical use of what would otherwise have been an unknown 
theory. In recognition of this fact the four-stroke cycle which Otto 
adopted in his engine and which is used in the majority of our 
modern motors is generally known as the Otto cycle. 

EXPLOSION=MOTOR CYCLE 

The cycle of the explosion motor, therefore, consists of four 
distinct steps, viz, (1) Admission of the charge of explosive fuel; 
(2) compression of this charge; (3) ignition and explosion of this 
charge; and (4) exhaust or expulsion of the burned charge. If this 
complete process requires four strokes of the piston rod in any one 
cylinder, the motor is designated as a four-cycle motor, although it 


4 


EXPLOSION MOTORS 


would be more exact to call it a four-stroke cycle. If the complete 
process is accomplished in two strokes of the piston, the motor 
is designated as a two-cycle motor. 

Four=Stroke Cycle. One complete operation of a single-cylinder 
Otto or four-cycle explosion motor is shown in Figs. 2, 3, 4, and 5. 
Fig. 2 shows the end of the first or suction stroke of the cycle. At 
the beginning of this stroke when about fe inch past the dead center 
the inlet valve A is opened by an eccentric rod whose movement is 
controlled by the eccentric on a secondary shaft driven through gears 
at half the speed of the motor. This allows the vapor supplied by 
the carbureter, which is an instrument for converting the liquid fuel 



into a vapor or gas, Fig. 6, to be drawn into the cylinder by the 
suction produced by the downward-moving piston. During this stroke 
the exhaust valve B has remained closed. 

The conditions shortly after the beginning of the second or 
compression stroke are shown in Fig. 3, both valves being closed. 
The piston, traveling as indicated by the arrows, compresses the 
charge to a pressure of about 60 pounds, when it is ignited at or 
before the end of the stroke by a spark taking place in the spark 
plug as shown in Fig. 4. Its arrangement is shown in detail Fig. 7, 
the spark passing between the points A and B. The force of the 
explosion drives the piston downward as shown in Fig. 4, which 
represents the power stroke. During these last two strokes, namely, 
the compression and working strokes, both valves if correctly timed 
should be completely closed. 

Fig. 5 illustrates the conditions existing after the piston has 


14 





























EXPLOSION MOTORS 


5 


begun the fourth or exhaust stroke. The exhaust valve B has been 
opened slightly before the end of the third stroke, and during this 
fourth stroke the gases are expelled from the cylinder through the 
open valve as shown. At the 
end of this stroke, piston and 
valves are again brought to the 
proper positions for the be¬ 
ginning of the suction stroke 
illustrated in Fig. 2. 

Compounding. The pres¬ 
sure is high at the end of the 
expansion in the Otto cycle, 
and the efficiency (the ratio 
of work gotten out to work 
put in) of the cycle can be in¬ 
creased considerably if the gas 
is expanded more completely. 

Ordinary steam engine prac¬ 
tice suggests that more complete expansion can be obtained by com¬ 
pounding. A compound steam engine has two or more cylinders. 
The steam or gas after doing work in the first or high-pressure cylinder 
completes its expansion in the other cylinder or cylinders. Thus far, 
however, no attempts to make a satisfactory compound gas engine 
have proved successful. The practical method of obtaining more 
complete expansion is to take into the 
cylinder a diminished charge. One method 
of accomplishing this is by controlling the 
amount of the opening of the admission 
valve, while the other is by controlling the 
time of closing of the admission valve. 

Double-Acting. One of the main ob¬ 
jections urged against the Otto cycle is 
that it requires two revolutions of the 
Fig. 7. Typical Form of Sparkplug engine for its completion, so that the ex¬ 
pansion or power stroke comes but once 
in four strokes. There results from this a very irregular driving effort, 
making large flywheels necessary if the main shaft is to rotate 
uniformly, or else requiring the use of several engines working on the 




Fig. 6. Typical Modern Carbureter with 
Water Jacket 

Courtesy of Ray field Carbureter Company, Chicago 


15 








6 


EXPLOSION MOTORS 



same shaft. The power strokes can be made twice as frequent if the 
cylinder is double acting, with admissions and explosions occurring 
on both sides of the piston. Many double-acting engines are used 
for stationary power purposes but not for automobiles. For the 
latter, the irregular driving effort in single cylinders is overcome 
by using a large number of cylinders, as four, six, or eight, so ar¬ 
ranged that the power impulses space out evenly. 


Two=Stroke Cycle. An increased frequency of the expansion 
or motive stroke can be obtained by a slight modification of the Otto 
cycle which results in the cycle being completed in two strokes, and 
which is consequently called the two-cycle method. Single-acting 
motors using the two-cycle method give an impulse every revolution, 
and consequently not only give a more uniform speed of rotation of 
the crank shaft, but also develop 60 to 80 per cent more power than 
four-cycle or Otto cycle motors of the same size. Moreover, they 
are generally of greater simplicity, having fewer valves than the four- 


Fig. 8. Vertical Section of Two-Cycle 
Smalley Motor 


Fig. 9. Vertical Section at Right 
Angles to View in Fig. 8. 


16 
































EXPLOSION MOTORS 


7 


cycle motors. An example is shown in Figs. 8 and 9 of a two-cycle 
motor of small size and of the two-port type; Fig. 8 is a vertical 
section showing the piston at the bottom of its stroke, and Fig. 9 is 
a vertical section in a plane at right angles to the previous section 
plane and showing the piston at the top of its stroke. As the trunk 
piston A makes its upward stroke, it creates a partial vacuum below 
it in the closed crank chamber C and draws in the explosive charge 
through B. On the downward stroke, the charge below the piston is 
compressed to about 10 pounds pressure in the crank chamber C, the 
admission through B being controlled by an automatic valve (not 
shown) which closes when the pressure in C exceeds the atmospheric 
pressure. When the piston reaches the lower end of its stroke, it 
uncovers exhaust port K and at the same time brings admission port 
D in the piston opposite the by-pass opening E, and permits the 
compressed charge to enter the cylinder G through the automatic 
admission-valve F, as soon as the pressure in the cylinder falls below 
that of the compressed charge. The return of the piston shuts off 
the admission through E, and the exhaust through K, and compresses 
the charge into the clearance space. The charge is then exploded, 
Fig. 9, and the piston makes its down or motive stroke. Near the 
end of the down stroke, after the opening of the exhaust port K, the 
admission of the charge at the top of the cylinder sweeps the burned 
gases out, the complete escape being facilitated by the oblique form, 
Fig. 8, of the top of the piston. The motor is so designed that the 
piston on its return stroke covers the exhaust port K just in time to 
prevent the escape of any of the entering charge. The processes 
described above and below the piston are simultaneous, the up-stroke 
being accompanied by the admission below the piston and compression 
above it, while the down-stroke has expansion above the piston and 
a slight compression below it. In large engines the charge is com - 
pressed by a separate pump, and not in the crank case. 

Six=Stroke Cycle. A recent development of somewhat prob¬ 
lematical outcome, but apparently of much promise, is the revival 
of the old six-cycle idea which has been quietly undertaken by a few 
manufacturers. 

During the earlier stages of the development of the explosion 
engine, we had what was termed a six-cycle or six-stroke-cycle engine, 
that is, one in which 6 strokes of the piston, or 3 revolutions of the 


17 


8 


EXPLOSION MOTORS 


flywheel are required for each power impulse or explosion. In 
addition to the operations taking place in the four-cycle engine, a 
third revolution of the flywheel, or two strokes of the piston, were 
employed for admitting and expelling a charge of pure air, imme¬ 
diately after the exhaust stroke had been finished. By thus ridding 
the cylinder of the burned gases, the early workers in the explosion 
motor field expected to obtain more economical results in fuel con¬ 
sumption. These expectations were not realized and as a result the 
six-stroke cycle was practically abandoned until now. 

The particular advantage sought by the use of this cycle is 
internal cooling of the motor. It is believed that the charge of cool 
air taken into the cylinder as a result of the addition of the two extra 
strokes to the ordinary four-stroke cycle will lower the temperature 
of the cylinder walls and piston and thus result in thoroughly adequate 
internal air cooling, secured at a slight sacrifice of frequency in the 
power stroke. 

TYPES OF EXPLOSION MOTORS 

Automobile Motors. Automobile motors are generally vertical, 
multicylinder, four-cycle engines, designed to run at speeds of 800 
revolutions per minute, or over, with long strokes, magneto ignition, 
four or more mechanically operated valves, using gasoline as a fuel, 
generally of the pair or en bloc type, and developing not more than 
16 horse-power per cylinder at 1,000 revolutions. The power is 
usually controlled by throttling with hand and foot adjustment. 

The horizontal arrangement is used sometimes with two opposed 
cylinders, that is, horizontal cylinders lying on opposite sides of the 
crank shaft and with their cranks at 180 degrees. Fig. 10 shows a 
chassis equipped with one of these motors. 

Two-cycle engines are also used occasionally, but so far have 
not met with much favor in automobile practice, an exception to 
this, however, being the motor shown in Fig. 11. This car met 
unusual success, as did one other prominent machine with a two- 
cycle engine, but was finally abandoned in 1912 because of other 
plans of the new owners of the Elmore plant. The other car, the 
Amplex, was discontinued in 1913 through the failure of the company 
marketing it. This leaves the American automobile field without a 
two-cycle adherent, although there is one very successful American 


18 


EXPLOSION MOTORS 


9 


motorcycle, the Shickel, with an engine of that form, and almost 
innumerable numbers of motor-boat engines of the two-cycle type 
still in use. On the other side, the English Valveless cars, Fig. 12, 
and Scott motorcycles present notable successes with the two-cycle 
engine. 

The peculiar points of interest and the differences in design 
from the accepted four-cycle form are as follows: Each piston 
has as its base an increase in diameter containing two packing 
rings. This part of the piston might be called the pumping piston 
and forms with the enlarged lower half of the cylinder a gas pump. 
When gas is driven out by this pump it does not go to the upper 
half of the same cylinder for firing, but it goes by way of the gas 



Fig. 10. Typical Horizontal-Opposed Engine for Commercial Car Chassis 
The Autocar Company, Ardmore, Pennsylvania 


distributor to the upper part of a different cylinder. This gas dis¬ 
tributor is the two-part cylinder running the full length of the motor. 

Cylinders . It is standard practice in automobile work to use 
either four or six cylinders arranged vertically in a row and usually 
with the cylinders cast in pairs, although the block form of casting 
is gaining most rapidly. 

Valves. There are several standard arrangements of valves 
in automobile motors. The two valves may be (1) both on one side 
of the cylinder; (2) one on each side of the cylinder; (3) both in the 
head; or (4) one on one side of the cylinder and one in the head. 
When more than two valves per cylinder are used, the arrangement 
varies from these, of course. With three valves, as used on the 


19 


10 


EXPLOSION MOTORS 



Fig. 11. Elmore Two-Cycle Valveless Motor 
Formerly Made by Elmore Manufacturing Company, Clyde, Ohio 



Fig. 12 Two-Stroke Valveless Engine 
Manufactured by David Brown and Sons, Huddersfield, England 


20 


















EXPLOSION MOTORS 


II 


Franklin car at one time, there were two concentrics, in the head and 
one on the side. Racing motors, with four valves per cylinder, 
usually have all four in the head or two in the head and two in the 
side walls at a 90-degree angle to the axis of the cylinder. 

The arrangement of an automobile motor cylinder with valves 
on opposite sides is shown in Fig. 13. This design requires two cam 
shafts, which are shown driven through an intermediate gear. Later 
practice uses a silent chain for this drive. The spark plugs may be 
over either set of valves or, with double ignition, over both. 



Fig. 13. Automobile Motor with Valves on 
Opposite Sides 


When the valves are placed on top, it is necessary to use levers 
between the push rods and the valves with some such arrangement 
as that shown in Figs. 18, 19, 20, and in detail in Figs. 22 and 23. 
The inlet valve is here placed over the exhaust. The latter is 
operated directly by a push rod. The inlet is worked by a separate 
push rod through a rocker arm, working from a fulcrum on the 
cylinder head. 

When both valves are overhead, a double arrangement like 
this is necessary or else an overhead cam shaft like that shown in 


21 









































12 


EXPLOSION MOTORS 


Fig. 14. This shaft is driven by bevel gears and another vertical 
shaft at the front end of the motor. The spark plugs are 
placed horizontally in the side of the cylinder, below the inlet 
manifold. 

A marked departure in valve construction is that shown in Fig. 
15, which is the Stearns-Knight type of sleeve valve motor. This 
valve action consists of two concentric sleeves sliding up and down 
between the piston and cylinder walls. These sleeves open and close 
the ports, which are side slots opening directly into the combustion 



Fig. 14. Overhead Valves Driven by Overhead Cam Shaft 
Courtesy of Maudslay Motor Company, Coventry, England 


chamber. These sleeves are moved up and down by small connect¬ 
ing rods from a crank shaft driven by a silent chain. 

Marine Motors. The principal difference between marine and 
automobile practice is in the much more extended use of two-cycle 
motors for small powers in motorboats. Where four-cycle motors 
are used they do not differ appreciably from automobile motors 
except in that they are generally stronger and heavier, and are often 
of larger size and lower speed. 

Motorcycles. The motor used in the motorcycle is of the 
ribbed, air-cooled, four-cycle, vertical type, usually single cylinder 


22 





EXPLOSION MOTORS 


o 

if 

? o 
> u 

a: u 
o 

tr 
2 O 


? a 

* i- o 

O u K 
* < 
o oc 
o w 
cr z 
_ a u 

/ft 


h 

z 

u 

-J 


23 



















14 


EXPLOSION MOTORS 




or V-twin cylinder. Some of the 
later models, however, are showing 
four-cylinder motors.* In Figs. 17 
and 18 are shown the standard types 
of engines found in motorcycles. 

Aeronautical Motors. The prin¬ 
cipal requirements of an aeromotor 
as compared with the motors pre¬ 
viously discussed are greater power 
per pound of weight, reliability, 
simplicity, freedom from vibration, 
and fuel economy. 

This field is just now receiving a 
great deal of attention from invent¬ 
ors and manufacturers. In fact, there 
have been within the past few years 
some hundred different makes of mo¬ 
tors offered to the public, which are 

Fig. 16. Single-Cylinder Motorcycle Motor of the tWO-Cyde Or foUr-Cycle type, 
Excelsior Motor Manufacturing and Supply . i , . . . . . . . 

Company, Chicago, Illinois either air-cooled or water-cooled, with. 

vertical, horizontal, or 
revolving cylinders. 

The principal aim 
of the majority of in¬ 
ventors seems to have 
been to reduce the 
weight. The average 
weight of these motors 
alone without acces¬ 
sories is about 3J 
pounds per horse-pow¬ 
er, few exceeding 4J 
pounds, the lightest 
one weighing only 1.8 
pounds per horse¬ 
power. However, it 
should be understood 


Fig. 17. Excelsior Twin Motor 


when considering this 





EXPLOSION MOTORS 


15 


remarkable weight, or rather lack of weight, that most of these 
motors can not be depended upon for a sustained flight of more than 
about one hour’s duration. The final developments will undoubtedly 
result in a somewhat heavier motor than these. 

MOTOR DETAILS 

FOUR=CYCLE TYPE 

While discussions of explosion motors must deal in fundamentals, 
a practical study of a standard type will give the greatest benefit to 



Fig. 18. Exhaust Side of Reo Automobile Motor 
Reo Motor Car Company, Lansing, Michigan 


the student. The motor chosen as the subject of this careful analysis 
of the functions of its parts and relations to the other parts is of the 
vertical, four-cylinder, four-cycle, water-cooled type, made by the 
Reo Motor Car Company. An exterior view is shown in Fig. 18, 
while detailed views of the motor are shown in Figs. 19 and 20. 

Valves. In each cylinder there are two valves, viz, the inlet 
and the exhaust. The inlet valve, which admits the explosive mix¬ 
ture to the explosion chamber, is located in a case in the cylinder 


25 






16 


EXPLOSION MOTORS 



Fig. 19. End View of Typical Motor 


Index of Parts to Motor, End View, Fig. 19 

I. Cylinder casting; 2. Crank shaft; 3. Crank case; 4. Plug for crank-case oil 
reservoir; 5. Vent pipe for crank case; 6. Cap for crank-case vent pipe; 7. Cam 
gear housing; 8. Inlet-valve lever; 9. Inlet-valve push rod; 10. Small cam gear; 

II. Large cam gear; 12. Valve spring; 13. Drive gear for magneto and pump; 
14. Drive shaft for magneto and pump; 15. Flywheel; 16. Oil-pump cylinder; 
17. Oil-gauge casting; 18. Fan support; 19. Fan blades; 20. Fan shaft; 21. Water 
pipe, pump to cylinder; 22. Drain plug for oil reservoir; 23. Drain cock for cyl¬ 
inder water jacket. 


26 






























Index of Parts to Motor, Side View, Fig. 20 

1. Connecting-rod cap; 2. Flywheel hub and clutch inner drive gear; 3. Drive 
bushing, flywheel to hub; 4. Flywheel; 5. Oil-pump body; 6. Oil-pump cylinder; 
7. Oil-pump plunger; 8. Eccentric for oil-pump drive; 9. Oil-pump cylinder 
head; 10. Oil screen, or filter; 11. Oil return pipe; 12. Circulating-pump body 
cover; 13. Impeller for circulating pump; 14. Body for circulating pump; 15. 
Large fan pulley; 16. Fan bracket; 17. Fan hub; 18. Fan blades; 19. Fan 
shaft; 20. Cap for fan hub; 21. Cylinder inlet water pipe, pump to cylinders; 
22. Cylinder outlet water pipe, rear cylinder to tee; 23. Cylinder outlet water 
pipe, front cylinder to tee; 24. Cylinder outlet water pipe, tee to radiator; 25. 
Magneto universal, drive-shaft end; 26. Disk for magneto friction; 27. Facing 
for magneto friction; 28. Spring for magneto friction; 29. Water-inlet pipe for 
intake heater jacket; 30. Cap screw for flywheel to hub; 31. Nut for cam gear 
housing cover, circulating pump, cover and water connections; 32. Nut for 
fan gear housing, valve lifter guide clamp, rear crank shaft bearing and exhaust 
manifold studs; 33. Nut for center cam shaft bearing lock screw; 34. Oil hole 
plug in fan hub; 35. Drain plug for oil pump; 36. Drain cock for circulating 
pump; 37. Elbow for oil return pipe; 38. Position screw for valve lifter guide; 
39. Lock screw for center cam shaft bearing; 40. Ball valve for oil pump; 41. 
Grease cup in flywheel for clutch outer driving member; 42. Piston; 43. Ex¬ 
haust-valve cover; 44. Piston ring; 45. Compression relief cock; 46. Exhaust 
manifold; 47. Cylinder casting; 48. Inlet valve chamber; 49. Exhaust valve 
stem guide; 50. Crank shaft; 51. Crank case; 52. Rear crank shaft bearing; 
53. Cam gear housing cover; 54. Oil shield between cylinders and crank case; 
55. Cam gear housing; 56. Magneto drive-shaft bushing in cam gear housing; 
57. Exhaust valve; 58. Valve lifter; 59. Valve lifter guide; 60. Valve lifter 
end; 61. Clamp for valve lifter guide; 62. Inlet valve lever; 63. Inlet valve 
push rod; 64. Small cam gear; 65. Center bearing for cam shaft; 66. Rear 
bearing for cam shaft; 67. Cam shaft; 68. Inlet cam; 69. Exhaust cam; 70. 
Valve spring; 71. Drive gear for magneto and circulating pump; 72. Inlet 
valve; 73. Connecting rod. 


27 

















































































































Fig. 21. Assembled Cam Shaft, Reo Motor 



Index of Parts, Valve=Opening Mechanism, Figs. 22 and 23 

1. Inlet valve; 2. Exhaust valve; 3. Valve lifter; 4. Valve lifter guide* 5. 
Valve lifter end, 6. Adjusting screw for inlet valve; 7. Adjusting screw for 
exhaust valve; 8. Locknut for valve adjusting screw; 9. Valve lifter roller- 
10. Valve lifter guide screw; 11. Inlet valve lever; 12. Roller for inlet valve 
lever; 13. Inlet valve lever support; 14. Inlet valve push rod: 15. Cam shaft* 
16. Inlet cam; 17. Exhaust cam; 18. Valve spring 


28 














































EXPLOSION MOTORS 


19 


head. The exhaust valve, 
which is so timed as to per¬ 
mit of the expulsion of the 
burned gases at regular in¬ 
tervals from the cylinder, is 
located in a pocket at the 
side of each cylinder. Fig. 
21 shows the assembled cam 
shaft, the cams of which 
control the opening and 
closing of these valves. The 
final angular displacement 
of each cam is determined 
by test for each individual 
motor. In the figure are 
also shown the driving gear 
and bearings. Figs. 22 and 

23 show in detail the oper¬ 
ating mechanism of the ex¬ 
haust and inlet valve. 

Valve Timing. In Fig. 

24 is shown the flywheel, 




Fig. 25. Assembled Crank Shaft 


upon the face of which are the following marks: 10, the point at 
which inlet valve opens; IC, the point at which inlet valve closes; 


29 






































20 


EXPLOSION MOTORS 







30 


Fig. 26. Diagram of Intake Manifold and Generator Attachment 


























































































































































































EXPLOSION MOTORS 


21 


Index of Parts, Intake Manifold, Generator Attachment, and Water 

Pipes, Fig. 26 

1. Intake manifold; 2. Cylinder inlet water pipe cylinder to cylinder; 3. Cylinder 
inlet water pipe, pump to cylinders; 4. Lug on cylinder outlet water pipe for 
intake heater connection; 5. Cylinder/outlet water pipe, rear cylinder to tee; 
6. Cylinder outlet water pipe front cylinder to tee; 7. Cylinder outlet water 
pipe tee to radiator; 8. Generator universal drive shaft end; 9. Drive shaft for 
generator and pump; 10. High tension cable tube; 11. Short arm for spark con¬ 
trol; 12. Long arm for spark control; 13. Pull rod for spark control; 14. Rocker 
shaft for spark control; 15. Intake pipe; 16. Water intake for intake heater 
jacket; 17. Water outlet pipe for intake heater jacket; 18. Drain cock for water 
pipe and pump; 19. Distributor; 20. Generator; 21. Pump. 



Fig. 27. Wiring Diagram for Battery and Generator Ignition System 


EO, the point at which exhaust valve opens; EC, the point at which 
exhaust valve closes; UDC, 1 and 4, upper dead center for cylinders 
1 and 4\ and UDC, 2 and 3 (not shown in figure), upper dead center 
for cylinders 2 and 3. 

These points are a guide as to where the inlet and exhaust 
valves of each cylinder should open and close. The small boss upon 
cylinder 4 marked with an arrow, Fig. 24, is taken as a reference 
point for the valve timing. 

The cylinders'are numbered 1,2,3, and 4 > the first one being 
next to the radiator. The same markings on the flywheel that serve 
for cylinders 1 and 2, also serve for cylinders 4 and 3, respectively, 
since, as a glance at the crank shaft, Fig. 25, shows, these points 
are exactly one-half revolution or 180 degrees apart. 

Ignition. The system of ignition used on the motor consists of 
a combined generator, magneto-timer and distributor shown in 


31 










































22 


EXPLOSION MOTORS 


diagram in Figs. 26 and 27, and in full view, Fig. 28. It is virtually 
a magneto system in which the permanent magnets of the ordinary 
magneto are replaced by electromagnets, which enables the gener¬ 
ator to produce sufficient current for ignition, starting, and lighting. 
A storage battery in which to store current is a necessary part of 
this system. The ignition switch is located on the steering post 
near the dash. The spark coil is mounted on the dash underneath 


ro CHARGE BATTERY WITHOUT 



BREAKER AND DISTRIBUTOR HEAD’ 


REMY ELECTRIC CO 

i ANDERSON INO I 
! MODEL rest *j 

nr VOLTS I-AM? 

SERIAL NO rw I 


GREASE CUP 


'ARMATURE SHAFT 


REMOvinG.connzcr hcre 
CONDENSER TERMINALS- 
WIRE TO CO/L- 

WIRES TO BREAKER 
WIRE TO AMMETER 
WIRE TO POSITIVE BATTERY TERMINAL- 
WIRE TO JUNCTION BLOCK 
OIL HERE 


Fig. 28. Generator for Supplying Ignition, Starting, and Lighting Current 
Courtesy of Reo Motor Car Company, Lansing, Michigan 


the cowl. There is no adjustment to make in connection with the 
coil; a safety gap is provided for its protection on the distributor. 
The condenser and distributor are shown mounted on the generator, 
Fig. 28. This system is simply used as a type. Many other systems 

Index of Parts, Carbureter, Fig. 29 

1. Float chamber; 2. Constant air connection; 3. Spray nozzle coupling; 4. Cork 
float; 5. Spray nozzle; 6. Needle valve; 7. Choke throttle valve; 8. Choke throttle 
lever; 9. Throttle gate; 10. Throttle gate stop; 11. Gasoline pipe connection; 
12. Gasoline valve; 13. Float lever; 14. Float lever studs; 15. Primer. 








Fig. 29. Johnson Carbureter 



33 




















































































































































































24 


EXPLOSION MOTORS 




34 


Fig. 30. Typical Oiling System on an Explosion Motor 










































































































































































































































































EXPLOSION MOTORS 


25 


Index of Parts, Oiling System, Fig. 30 

LnrSaftbeirfne R 4 ar r‘; rank sha {, t b, ? arin g; 3 - Cap for front and center 
Snalt bea £ ln g» 4 - Cam gear housing cover: 5. Cam gear housing- fi 

1^ Frnn?p gear; J> + L u rge - Cam gear ; 8 * Center cam shaft bearinl; 9. Cam shkfC 
10. Front cam shaft bearing; 11 . Upper oil pump body; 12. Oil pump cylinder 1 

plunger; 14 A Eccentric for Oil pump drive; 15. Oil puZpYyffi 
nfnp ’f 1 0lI , SC [ ee r? ? r fi . lter >’ 17 ' Tee for cra "k shaft oil pipe; 18. Main oil 
cental 01 cra |P k shaft bearings; 19. Outlet pipe for oil pump; 20. Oil pipe for 

? 3 nt B;n r v a a n ive S fo a r f oUpu r m r ?: “• °“ retUm ^ 22 ' Dra “ P 1 ^ ***&£; 
are in common use and are described in detail in 
books on this subject. 

In Fig. 19 the cam gear housing is shown with 
the cover removed. The crank-shaft gear 10 is 
keyed to the crank shaft and revolves with it. 

The large cam-shaft gear 11 is rigidly fastened to 
the cam shaft, and revolves in the opposite direc¬ 
tion just half as fast as the crank-shaft gear. The 
magneto gear is fastened to the magneto and the 
pump drive shaft. This gear revolves in the same 
direction and at the same speed as the crank shaft. 

The carbu¬ 
reter, shown in 
detail in Fig. 29, 
which supplies 
the gasoline va¬ 
por to the intake 
manifold, is of 


the float 
automatic 
valve type. 

Motor 

brication. 


feed 


Lu= 

The 



Fig. 31. Fan Details. 1. Fan Bracket; 2. Fan Hub; 3. Fan Blades; 
4. Fan Shaft; 5. Hub Cap; 6. Oil-Hole Plug; 7. Ball Bearings 


oiling system of 
this motor, 
shown in Fig. 30, 
is an integral 

part of the motor and consists principally of a single large plunger 
pump driven by an eccentric from the cam shaft. The oil is forced 
through the pipes inside the crank case to the crank-shaft bearings 
and from there to the faces of the cam gears. The oil then flows 


35 




















































26 


EXPLOSION MOTORS 


to the reservoirs in the bottom of the crank case where it is main¬ 
tained at a constant level and from which it is picked up by scoops 
on the bottom of the connecting rods and distributed in a fine spray 
to the pistons, cylinders, and bearings. 

Cooling System. The cooling system in a motor, i.e., the system 
by which the cylinders are prevented from becoming too hot, con- 



Fig. 32. Typical Radiator 


sists chiefly of a fau, shown in detail in Fig. 31 j a 'puTR'p for supplying 
the cooling water, shown along with the generator drive shaft in 
Fig. 26, and a vadicLtor, Fig. 32, which connects with the water 
outlet pipe and with the water pump at 13, both shown in Fig. 20. 

Clutch. The connection which must be established between 
the crank shaft of the motor and the main drive shaft running to 
the rear axle is made by means of a clutch, in this case of the mul¬ 
tiple-disk type shown in detail in Fig. 33. The relation of these 
various parts to the rear wheels is very clearly shown in Fig. 34. 

Crank and Firing Arrangements. The order in which the 
explosions should take place in the cylinders and the best arrange- 


36 












































































































EXPLOSION MOTORS 


27 


ments of cranks for multi-cylinder, four-cycle motors are shown in 
diagram in Fig. 35. 

Two-Cylinder Motor. With the cranks set at 180°, Fig. 35A, 
the two cylinders fire one-half revolution apart and hence, during 
one revolution there are two power strokes and at the next no 
power stroke. 

Index of Parts, Radiator, Fig. 32 

1. Stud for fastening radiator to front cross frame; 2. Lower tank body; 3. 
Lower tank cover; 4. Filler pipe; 5. Outlet pipe; 6. Inlet pipe for radiator; 
7. Fins for radiator; 8. Stay rod for radiator; 9 Internal intake pipe for radia¬ 
tor; 10. Upper radiator tank body; 11. Cover for upper radiator tank; 12. 
Radiator tubes; 13. Radiator overflow pipe; 14. Reinforcement for radiator 
fins; 15. Radiator connection for intake heater outlet pipe; 16. Screen for 
radiator filler pipe; 17. Drain cock for radiator. 


Index of Parts, Clutch, Fig. 33 

1. Crank shaft; 2. Flywheel hub; 3. Flywheel; 4. Block for clutch transmission 
universal; 5. Relief sleeve for clutch; 6. Nut for crank shaft; 7. Facing for large 

clutch disk; 8. Thrust mem¬ 
ber for clutch; 9. Large 
washer for clutch thrust 
bearing; 10. Small washer 
for clutch thrust bearing; 
11. Clutch driven gear and 
universal fork; 12. Drive 
shaft for clutch transmission 



Fig. 33. Multiple-Disk Clutch 


universal; 13. Bushing for 
clutch driven gear; 14. Ball 
cage for clutch thrust bear¬ 
ing; 15. Clutch closing spring; 
16. Small disk for clutch; 17. 
Large disk for clutch; 18. Bearing for 
clutch driven gear; 19. Retainer for clutch 
relief collar; 20. Cover for clutch universal; 
21. Bolt for clutch closing spring; 22. 
Relief collar for clutch. 


37 


























































28 


EXPLOSION MOTORS 









38 














































3 


C 


A 



TWO CYL/NDER 
CRANKS AT /80° 






/ 

z 


1 


r~i 


r 


TITO CYL/NDER 
CRANED AT360° 




TYREE CYLINDER 
CRANES AT /YO° 
F/RED f-3-R 


n 



E 



[rr-- -=} 








Z 

C-~" 




5 

- ! 

1 




3 




< 


-t-i 

— T* 

V 

J L 



-t— 


FOUR CYL/NDER 
CRANKS AT /<30° 
F/RED J-3-R--Z 


S/X CYLINDER 
CRANKS AT /go 
F/RED J-5-3 6 R-R- 



OPPOSED CY//NDER NOR/ZONTAL ENG/NE 
CRANKS A " r /80 ° 



TV/O CYL/NDER VTYPE ONE CRANK 
CYL/NDERSAT 95 °(USUALLY) 



E/CRT CY//NDER Y TYPE CRANKS AT /80° 
E/RED - ZEAL -JR- EL - 9R -/L~ PR - 3L 


Fig. 35. Crank and Firing Arrangements for Multicylinder Four-Cycle Motors 


39 




















































































































































































30 


EXPLOSION MOTORS 


With the cranks set at 360°, Fig. 3 5B, we get a power stroke 
at each revolution. This arrangement, however, requires careful 
balancing to counteract the vibration which results from all parts 
moving in the same direction at the same time. The order of action 
in the two cases is given as follows: 


180 : 


First Cylinder 
Suction 
Compression 
Firing 
Exhaust 


Second Cylinder 
Exhaust 
Suction 
Compression 
Firing 


First Cylinder 
Suction 
Compression 
Firing 
Exhaust 


360 ° 

Second Cylinder 
Firing 
Exhaust 
Suction 
Compression 


If the amateur finds the above difficult to follow, it may be 
simplified as follows: Duplicate the actions below those given, that 
is, repeat the action in two revolutions. Then mark off at the left 
the revolutions, indicating the first pair of actions for one, the second 
for two, etc. This applies right across the table. Then, one notes 
that the firing in the first cylinder comes on the second revolution 
and the first stroke, while that in the second cylinder comes on the 
same revolution but the second stroke. This gives two firing 
impulses on one revolution, followed by another with none, then two 
more firing, etc. In the cylinders set at 360°, it will be noted that 
the second cylinder fires on the first stroke of the first revolution, 
while the first follows, firing on the first stroke of the second revo¬ 
lution, then the second on the first of the third, and the first on the 
first stroke of the fourth, etc., thus distributing the firing evenly. 

Four-Cylinder Motor. In the four-cylinder motor of the four¬ 
cycle type, we have two power strokes for each revolution of the 
crank shaft or flywheel. In order to secure smooth working, these 
power strokes should occur exactly one-half revolution apart. From 
Fig. 35 D it will be seen that the four-cylinder crank shaft has two 
pairs of cranks just one-half revolution apart, pistons 1 and 4 moving 
up, while pistons 2 and 3 move down, or vice versa. • 

Suppose for instance, that piston 1 has just been forced down 
on the power stroke. Then pistons 2 and 3 will be up and one of 
these should be ready to receive the force of the explosion, and 
should have, therefore, just compressed an explosive charge in its 
cylinder ready to be ignited. For the sake of illustration let us choose 
piston 3 to make the next power stroke. Piston 3 now moves down 


40 




EXPLOSION MOTORS 


31 


and pistons 1 and 4 move up. Since it is evidently impossible to 
have piston 1 contain an explosive charge without giving it one more 
up and down motion, piston 4 must make the next power stroke. 
This piston, therefore, moves down as a result of the explosion in 
cylinder 4, and it is now necessary for piston 2 to make the next 
power stroke. Thus the order of firing is 1-3-4-2. 

A study of Figs. 35(7, 35 F, and 3 5E will show the method of 
firing in the cases of the three-cylinder, the two-cylinder horizontal- 
opposed motors, and the six-cylinder, respectively. In Figs. 35(7 and 
35 H will be found the corresponding methods for the two-cylinder 
and eight-cylinder V types. The last named is more difficult to 
follow out, but by treating it as a pair of fours which must fire first 
in one pair and then in the other, and considering this in conjunction 
with 35 B, the scheme of arrangement will be plain. The actual 
order used on De Dion (French) and Cadillac motors is 1R, 4L, 3R, 
2L, 4R, 1L, 2R, 3L. 

Just as the firing order of the eight, or twin four, is followed 
through by considering it as a pair of fours, so the twelve or twin 
six may be considered as a pair of sixes. There is this important 
difference between the eight and the twelve, however; in the eight 
the two sets of cylinders are set at an angle of 90 degrees with 
each other, while in the twelve, the two “six groups” are usually set 
at 60 degrees. This makes a different interval in the firing; the 
firing order of any twelve might be 1R, 6L, 5R, 2L, 3R, 4L, 6R, 
1L, 2R, 5L, 4R, 3L. 

Theory of Crank Effort. One-Cylinder Motor. In a single¬ 
cylinder motor, four strokes of the piston are required to complete 
its cycle, i. e ., the suction stroke, compression stroke, power stroke, 
and exhaust stroke. Note that only one of these strokes, the third, 
makes power. Roughly speaking, power is not produced throughout 
even the entire part of this stroke, but only through about four- 
fifths of it. Hence, in a single-cylinder motor with a 5-inch stroke, 
the piston travel for one complets cycle will be 20 inches. In only 
about 4 inches of this distance is power produced. (S*ee Figs. 36 
and .37) Hence four-fifths of the total piston travel is a non-pro¬ 
ducer of power. 

Two-Cylinder Motor. In the two-cylinder motor we have two 
power strokes to the cycle, as follows: 


41 


32 


EXPLOSION MOTORS 


First Stroke Inches of Power 

Cylinder 1 Suction 

Cylinder 2 Power 

Second Stroke 

Cylinder 1 Compression 0 

Cylinder 2 Exhaust 0 


Third Stroke 

Cylinder 1 Power 4 

Cylinder 2 Suction 0 

Fourth Stroke 

Cylinder 1 Exhaust 0 

Cylinder 2 Compression 0 

Total inches of piston travel representing power. . 8 

Total inches of piston travel. 20 


Hence, the motor furnishes power during only 40 per cent of the cycle. 


Four-Cylinder Motor . With the four-cylinder motor we have 
one power stroke during each half revolution of the crank shaft. 


GREATEST PRESSURE - 

AVERAGE PRESSURE 
NO PRESSURE 


POWER STROKE IDLE POWER STPME ME POWER STROKE /DIE POWER STROKE /ME 



gREV. /REV /§REV. 

CRANK SHAFT REVOLUTIONS. - 



AVERAGE 


/VO PRESSURE ; 


GREATEST PRESSURE //V\ POKER STROKE POWER STROKE POWER STROKE POWER STROKE POWER STROKE POWER STROKE 
A FOUR OR EQUAL POWER) 1 
GREATEST PRESSURE /NX/ 

THE S/X 


CRANK SHAFT REVOLUTIONS. 


/§REV. EREV 


A FOUR CF EQUAL POWER 
GREATEST PRESSURE IN], 
A S/X OF EQUAL POWER J 
AVERAGE PRESSURE- 


A V PRESSURE- 



POWER 

POWER 

POWER 

POWER 

POWER 

POWER 

POWER 

POWER 

J 

) 

STROKE 

STROKE 

STROKE 

STROKE 

STROKE 

STROKE 

STROKE 

STROKE 

: ' 










|jj 





*QW£ 


■ 


K-REV 


EREV. 4REV /REV / 4 REV /sREV /4REV EREV 
CRANK SHAFT REVOLUTIONS. 


Fig. 36. Curves Showing Duration of Power in Four-, Six-, and Eight-Cylinder Motors 


This gives us power during 16 inches of piston travel or power during 
88 per cent of the entire cyle. 

Six-Cylinder Motor . In the six-cylinder motor (the cylinders 
being the same size as those above considered, and the stroke the 


42 


































EXPLOSION MOTORS 


33 


same) we have 4 inches of power produced by each cylinder, making 
a total of 24 inches of power with a total piston travel of 20 inches. 
On the basis of the percentage values given in the two- and four- 



Fig. 37. Power Distribution Chart in Various Motors 


cylinder types this would mean an application of power during 120 
per cent of the cycle. As this is impossible and as the six cylinders 
are evenly spaced, the power in the cylinders must overlap each 
other. This results in continuous power. Diagrams showing the 
relation between the application of power in the four-cylinder motor, 
in the six-cylinder, and in the eight-cylinder, are shown in Fig. 36. 



Eight-Cylinder Motor. In the eight-cylinder motor—the cyl¬ 
inders being of the same size as those considered previously, and the 
stroke the same—we have 4 inches of power produced by each 
cylinder, making a total of 32 inches of power with a total piston 
travel of 20 inches. On the basis of the percentage values given 


43 
































34 


EXPLOSION MOTORS 


for the other types, this would mean the application of power over 
more time in the cycle than is possible, so, as in the case of the six- 
cylinder motor, there is an overlap. In this instance, however, 
the overlap is three times as great as in the six-cylinder, consequently 
the delivery of power is that much more even and continuous. 

Twelve-Cylinder Motor. In the twelve-cylinder motor, with 
the same size cylinders as before, we have the same 4 inches of 
power in each cylinder, or 48 inches total, with a total piston travel 
of 20 inches, showing again a large amount of overlap. Here the 
overlap is seven times as great as in the six-cylinder form, conse¬ 
quently the output of power should be that much more even. 

The diagram of Fig. 37 gives a clear idea of this distribution 
of power in the various motors discussed except that the twelve is 
not shown. The difference between the twelve and the eight is 
approximately the same as between the eight and the six, the over¬ 
lap of the power strokes for the twelve being so great as to make 
the white notches almost disappear. 

Effect of Dead Centers. In both the two- and four-cylinder 
motors, the cranks being set 180 degrees apart, each piston is always 
one complete stroke ahead of the succeeding one. When the cranks 
of the motor are as shown in Fig. 38 ( a ) in direct line with the con¬ 
necting rod, the entire motor is on dead center. Fig. 38 ( b) shows 
the same condition with offset cylinders. 

In the six-cylinder motor, the cranks are set at 120 degrees, 
Fig. 38 (c), and, therefore, we have no condition when the entire 
motor is on dead center. It is impossible to have more than two of 
the cranks on dead center at once. Hence, there is never a time in 
the six-cylinder cycle when the motor does not produce power. 

In the eight-cylinder V-type motor the cranks are set 180 
degrees apart, as in the four-cylinder form, but the cylinders are set 
at 90 degrees, 45 each side of a vertical, as shown in Fig. 38 {d). 
The connection of the side by side cylinders of each pair of fours to a 
common crank pin—the two number one cylinders, for instance, 
working on the first pin, the number twos on the second, etc.— 
eliminates all dead centers. This is one advantage of the V-type 
over the straight-line type for the latter has a dead-center cylinder. 

In the twelve-cylinder V-type motor, the cranks are set at 120 
degrees as in the six, but the cylinders are set at 60 degrees, 30 on 


44 


EXPLOSION MOTORS 


35 


each side of the vertical, the only difference from Fig. 38 ( d ) being 
in the angle. The crank-pin attachment in the twelve is similar to 
the eight, the first two cylinders working on the first crank pin, the 
second two on the second pin, and so on. Obviously the form of the 
crank and the setting of the cylinders at an angle eliminate all dead 
centers. 



Fig. 39. Front View ol Fight-Cylinder V-Type Motor 
Courtesy of Cadillac Motor Car Company, Detroit , Michigan 


Power Exerted against the Pistons. In a single-cylinder, 48- 
horse-power motor the explosion of the mixture practically results 
in the striking of a hammer blow against the piston of 28,800 
pounds. In a four-cylinder, 48-horse-power motor each piston 
receives a blow only one-fourth as great, or 7,200 pounds. In a 


45 






36 


EXPLOSION MOTORS 


six-cylinder, 48-horse-power motor each piston receives only 4,800 
pounds. Similarly, in an eight-cylinder 48-horse-power motor each 
piston receives a blow of 3,600 pounds. Compared with the four- 
cylinder motor, this is a reduction of one-half; relative to the six- 
cylinder, it is a reduction of one-fourth. 

So too, with the twelve-cylinder, 48-horsepower motor each 
piston receives a blow of only 2,400 pounds, one-half the blow exerted 
in the six-cylinder motor and two-thirds the blow exerted in the 
eight. It is this small amount of hammering which makes the mul- 



1 Fig. 40. Front View of Twelve-Cylinder V-Type Motor with Overhead Valves 
Courtesy of Enger Motor Car Company, Cincinnati, Ohio 


tiple cylinder motor—in either eight- or twelve-cylinder form—much 
more quiet and easy running than can ever be the case with the 
four- or six-cylinder forms. In addition, the small size of the pistons 
for equal power development allows a much stiffer and stronger con¬ 
struction, even when a lighter metal, like aluminum or any of the 
various aluminum alloys, is used. The lighter reciprocating parts 
increase the output per cubic inch of cylinder, thus making the 
multiple type of motor relatively more efficient. 

Repair Man’s Interest in Multiple Cylinders. Every repair 
man should be well posted on eights and twelves for two reasons. 
In the first place, the average owner knows little about them, and 
as he considers that the repair man knows all about every kind of 


46 






EXPLOSION MOTORS 


37 


motor, he will go to him for information at the first sign of trouble. 
In the second place, the repair man should be able to handle and 
repair these forms of motor, for the fact that they have more parts 
and are more complicated makes them more likely to need skilled 
attention. Moreover the average owner, knowing of this greater 
complexity of construction, will be averse to turning his eight or 
twelve over to any but the best repair men—skilled mechanics with 
a thorough working knowledge 
of the principles of the new 
motors. Any intelligent re¬ 
pair man with a thorough 
knowledge of the principles 
around which these new motor 
forms are built, and with an 
equally thorough and intimate 
knowledge of how fours and 
sixes are constructed, ad¬ 
justed, and repaired, need have 
no fear to tackle any kind of 
engine new or old. 

SMALL GAS ENGINE 

The general practice with 
small stationary engines differs 
quite radically from the stand¬ 
ard motor practice just con¬ 
sidered. However, as the fields 

of the tWO Overlap, the disCUS- Flg ' 41 • Stationary Engine with Single Valve 

sion of the small stationary type at this point will not come amiss. 

Two=Cycle Type. A modification of the type of explosion 
motor shown in Figs. 8 and 9, which makes its construction 
even more simple, is the use of a single valve—an automatic 
valve which admits the charge to the crank case. In this 
engine, Fig. 41, the series of operations is precisely similar to 
that described for Fig. 8, the only difference being in the 
by-pass connection E, which has no valve between it and the 
cylinder. The exhaust is made to open a little earlier than the 
admission, so as to make sure that the pressure in the cylinder 



47 









38 


EXPLOSION MOTORS 


shall have fallen below the pressure of the slightly compressed charge 
when the admission port opens. If the opening of the exhaust and 
admission ports were simultaneous, as in the engine just described, 
some of the exhaust gases would force their way through E to the 
crank case, and, being at a high temperature, would ignite the charge 
there. The piston is so shaped that the entering charge is directed 
to the top of the cylinder, forcing out the burned gases before any 
of the charge can escape through the exhaust port. 

In place of the automatic inlet valve at B, there is sometimes 
used a revolving disk valve turning with the crank and containing 
a slot which registers with the crank case inlet during part or all of 
the up-stroke of the piston. The disk is pressed against its seat by 




Fig. 42. Smalley Three-Port Two-Cycle Motor 

a light spring. This arrangement controls the admission of the 
charge to the crank case, permitting of adjustment of the duration 
of admission, and consequently of the volume admitted. It sac¬ 
rifices, however, the reversibility of the engine. 

A further and last modification of this engine makes it entirely 
valveless and of the utmost simplicity. This feature is illustrated 
in Fig. 42. The admission of the charge is through the port B, which 
is covered and uncovered by the piston, and which consequently does 
not require any automatic valve. During the up-stroke of the pis- 


48 







































EXPLOSION MOTORS 


39 


ton, a vacuum is created in the closed crank case, till near the top 
of its stroke, when the admission port B is uncovered, and the 
explosive charge rushes into the crank case, filling it until the pressure 
there is approximately atmospheric pressure. The rest of the opera¬ 
tions are exactly as in the engine just described, the charge being 
compressed in the crank casing during the down-stroke, and then 



WEIGHT 


GRID VALVE 


FUEL INLET VALVE! 


FUEL RESERVOIR 


WATER OUTLET 
ELECTRIC IGNITER 


PISTON RING 
PISTON PIN 

PISTON 
IGNITER ROD 

CYLINDER OILER 


GOVERNOR 

SLEEVE 


CRANK SHAFT 


PINION 


CRANK 


FLY WHEEL-*- 


BEARING PLATE 


FLY WHEEL 


AUXILIARY 


VALVE ROD 
FUEL PIPE- 


GOVERNOR 
GEAR 


Fig. 43. Vertical Four-Cycle Stationary Engine 
Courtesy of Fairbanks , Morse and Company 


transferred through a port D, in the hollow piston, and through the 
port E in the cylinder wall, to the upper side of the piston when this 
latter is near the end of its down-stroke. This modification is gen¬ 
erally known as the three-port type of the two-cycle motor. 

Four=Cycle Type. Figs. 43 and 44 illustrate the details of a 
standard vertical four-cycle type of engine. This engine may be 


49 
























40 


EXPLOSION MOTORS 


equipped with a carbureter as in automobile practice, but is more 
often provided with a pump, Fig. 45, which introduces the fuel 
directly into the cylinder in the form of fine spray. 

Ignition. In this type instead of producing ignition by means 
of a spark plug, the spark is usually obtained by making contact 



OIL DRAIN 


Fig. 44. Vertical Four-Cycle Stationary Engine 
Courtesy of Fairbanks, Morse and Company 


exhaust valve rocker arm 


EXHAUST PIPE 

EXHAUST VALVE 

EXHAUST ROD 

PISTON RINGS 
OIL CUP 

EXHAUST ROCKER 

EXHAUST ROLLER 
GOVERNOR WEIGHT 


GOVERNOR 

SPRING 


SPLASHER 


PLUG 


'CYLINDER 


WATER INLET 

CONNECTING ROD 

HAND HOLE 
PLATE 


FUEL INLET VALVE LOCK 


CYLINDER HEAD 


and breaking contact between the electrodes or contact points of 
what is called a “make-and-break” igniter, shown in Figs. 43 and 46. 

The igniter plug in Fig. 46 has been removed from the cylinder 
head. The movable electrode B is at the end of an arm which is 
fastened to the spindle C. When the interrupter lever Z), which is 
loose on the spindle C, and is connected to it through a coiled spring, 
is lifted by an arm from the cam shaft of the engine, it rotates the 


50 















EXPLOSION MOTORS 


41 


spindle C so as to bring B into hard contact with the stationary and 
thoroughly insulated electrode A. This completes a circuit and 
permits a current to flow from A to B. When ignition is desired the 



Fig. 45. Pump for Liquid Fuels 
Courtesy of Fairbanks, Morse 
and Company 



Fig. 46. Igniter Plug 



Fig. 47. Spark Coil 
Courtesy of Thordarson Electrical 
Manufacturing Company 



lever D is tripped and flies back, carrying with it the shaft C, abruptly 
breaking the contact and causing an electric arc to form between 
A and B. The spark from an ordinary battery is greatly increased 


51 




































42 


EXPLOSION MOTORS 


by allowing the current to flow through a make-and-break ignition 
coil, Fig. 47, which consists of a coil of insulated copper wire in which 
a laminated magnetic circuit is used in connection with an air gap. 
The igniter circuit is arranged as in Fig. 48. 

Governing. Stationary engines are governed by either the 
“hit-and-miss” governor or the throttling governor, the latter being 
the form used in practically all motors. The action of the throttling 
governor is such that more or less fuel is admitted at each charge, 
according to the load, the richness of the mixture remaining the 
same and the engine making regular explosions. With the hit-and- 
miss governor, a greater or less number of fuel charges are admitted 
to the cylinder according to the load on the engine, the mixture and 
the quantity of each charge always remaining the same. The result 
of this is that the number of explosions per minute will vary with 
the load. 

THERMODYNAMICS OF THE EXPLOSION MOTOR 

In explosion motors the explosive mixture in the cylinder 
consists of air mixed with a smaller volume of the vapor of the 
liquid fuel. This mixture will behave up to the time when explosion j 
takes place, practically as if it were merely air. Also the products 1 
of combustion, after the explosion is completed, have physical 
properties differing only slightly from those of air, and consequently 1 
the working substance in the cylinder may without serious error be 
regarded as consisting entirely of air. In the discussion of what 
occurs in the engine cylinder, this assumption is made. 

Indicators.* In order to more clearly understand what follows, 
it is necessary to have some knowledge of the indicator diagram. 
These are made by two forms of engine indicator, the modified 
steam engine form which is satisfactory up to about 500 r. p. m. 
and the manograph used above that speed. The former is described 
as consisting of a drum carrying a sheet of paper which, by rotation, 
is moved an amount proportional to the piston travel. An arm 
whose motion is governed by the pressure in the cylinder carries a 
pencil which traces on the paper a diagram whose vertical values 
are proportional at every point to the pressures in the cylinder. 

♦See also page 62. 


52 



EXPLOSION MOTORS 


43 


Watt’s Diagram of Work. James Watt was the first to see the 
need of accurate knowledge of the action of steam in the cylinder 


of a steam engine and to him 
belongs the credit of devising 
and using the first indicator. 
Fig. 49 illustrates the method 
adopted by Watt. The hori¬ 
zontal line AC, called the 
abscissa, represents the length 
of stroke and is divided into 
ten equal parts. The vertical 
line AB, called the ordinate, 
indicates the pressure of the 
steam. 






«Fig. 50. Crosby Indicator in Part Section 


When the piston has moved from B to E, the steam is cut off, 
that is, a volume of steam equal to one-fifth the volume of the cylinder 






























































Fig. 51. Crosby Indicator Complete 








x^ig. 52. Crosby Indicator with External Springs 





' y „-/C\ 

' 


Ssillta§sll 




i m I 

• - ■. 

•s. '■ 

' -.v, A , , i?, % , .. ^ 








54 









































































































































































































EXPLOSION MOTORS 


45 


is allowed to expand until it fills the entire cylinder. The area of 
the figure BEDCA may be found by adding the several pressures 
shown by the vertical dotted lines, dividing by the number of divi¬ 
sions, and multiplying by the length AC. The study of similar 
diagrams on a small scale when drawn by an indicator represents 
the only method of obtaining a correct idea of the action of steam 
in the cylinder of a steam engine or of the mixture in the cylinder 
of an explosion motor. 

Figs. 50 and 51 show an inside and an outside view of the Crosby 
indicator. In gas engine work, the spring located as shown in Fig. 
49 is liable to be injured by heat. To lessen the difficulties due to 
this, most of the makers supply indicators with external springs, as 
shown in Fig. 52. 

Manograph. As has been stated previously, the steam engine 
form of indicator is satisfactory up to speeds of 500 r.p.m., but as 
the majority of gas and gasoline engine work is above that—particu¬ 
larly automobile and aeroplane motors in which the speed may 
reach a maximum of 4,000 r.p.m., while 1,000 r.p.m. would be 
considered a slow speed and 1,800 an average—some other form is 
necessary. The reason for this lies in the fact that at speeds above 
500 r.p.m., the inertia of the indicator piston, pencil arm, and 
other moving parts is so great that the diagrams become distorted 
and do not show a true shape compared with the events within the 
cylinder. Another difficulty lies in making the passages between 
the cylinder and the indicator large enough so that the pressure 
fluctuations in the motor cylinder will be followed exactly by those 
in the indicator cylinder and, consequently, be reproduced exactly 
in the diagram. 

These difficulties have led to the use of a device called the 
manograph. In this a beam of light travels over a visible ground 
glass of a darkened surface so as to be visible to the observer all of 
the time; or by replacing this with a sensitized piece of paper, pre¬ 
pared for the purpose, a print is made which must be developed and 
fixed the same as any photographic print. When the engine is 
being tested out for faults in the design and construction, the latter 
method is followed and the cards are preserved for future study and 
as a matter of permanent record. However, when the design and 
construction are satisfactory and the engine is simply being tuned 


55 


46 


EXPLOSION MOTORS 


up to its best performance, the former method is followed and no 
permanent records are kept. 

It can be seen at once that this is a tremendous advantage for 
the indicator diagram of the engine under test is visible at all times 
to the tester, who can increase or decrease engine speed and note at 
once the changes in the diagram, right in front of him; can alter 
carbureter or magneto settings and see at once the changes which 
these make in the diagram. To facilitate the use of this, it is made 
with as many compartments as the motor has cylinders, although 
all the illustrations which are shown indicate a single-cylinder outfit, 
which has, of course, only one compartment. 

This result is obtained by the use of a small aperture through 
which a beam of light is admitted to the interior of the box. At 
one end of the latter, there is a small concave mirror, upon which 
the beam of light impinges. This mirror is connected to the crank 
shaft or other moving part of the engine in such a way that the rota¬ 
tion of the motor imparts to the mirror a horizontal rocking move¬ 
ment limited to a small angle of, say 20 degrees. This movement 
is, of course, at a speed which corresponds with the speed of the 
engine. 

In addition, the mirror has a connection with the cylinders of 
the motor by means of which the pressures there are imparted to 
the mirror in a vertical direction, rocking it in that direction. The 
first motion that of rotation would make nothing but a straight 
horizontal line of a length proportional to the motor’s stroke and at 
a rate proportional to its speed. But by adding the motion pro¬ 
duced by the internal pressures, there is created a diagram or closed 
figure which represents accurately the events taking place within 
the cylinder. 

Description of Manogragh. A general exterior view of a mano- 
graph, the Carpentier (French), is shown in Fig. 53, with horizontal 
and vertical sections at Figs. 54 and 55, and a detail of the mechanism 
which moves the mirror at Fig. 56. In Fig. 53, it will be noted 
that it consists primarily of a light-tight box B, which is generally 
mounted on a tripod for convenience. To one end of this is fixed 
a casting A, inside of which the mirror is secured, together with 
the mechanism for causing its movements. A ground-glass screen 
C is shown partially withdrawn from its position on the front of the 


56 




EXPLOSION MOTORS 


47 


box, but, as has been explained, when a permanent record is desired, 
an ordinary photographic plate holder is substituted for this. A 
lamp D with an acetylene burner communicates with the interior 
by means of the tube E and furnishes the beam of light. 



The horizontal movement of the mirror is brought about by a 
crank and reducing arrangement, actuated by the flexible shaft e. 
This is driven directly by the motor crank shaft, a special taper 



Fig. 54. Horizontal Section of Carpentier Manograph 


socket being applied so that the flexible shaft may be connected or 
disconnected at will. In order that the motion of the beam of light 
and that of the piston shall correspond, an adjusting means is pro¬ 
vided in the chamber at the right by means of the screw F. 


57 



















































48 


EXPLOSION MOTORS 


The vertical movement which corresponds to the pressures 
in the cylinder is transmitted by means of the pipe G, which com- 



Fig. 55. Vertical Section of Carpentier Manograph, Showing Interior 
Arrangement 


municates with a diaphragm within the nut H. A pin bears against ] 
the center of the diaphragm and also against the back of the mirror. 
This may be seen in the vertical section, Fig. 55, in which this pin 
is marked I, and the mirror inside the box is marked J. 



In the horizontal section, Fig. 54, the interior arrangements 
are shown quite clearly, the lettering being the same as in Figs. 


58 
























































EXPLOSION MOTORS 


49 


53 and 55. Note how the beam of light from the lamp D passes 
through the tube E, is deflected by the prism against the mirror J, 
and then thrown on the screen or plate C. Referring to the detail 
view, Fig. 56, A, F, G, H, I, and J are the same as before. Gears 
n and m have an equal number of teeth, n being driven by the flexible 
shaft e. It will be noted that m carries a pin to which is attached 
a small connecting rod l. This is attached to the lever k, which is 
pivoted on the small screw o shown about midway of its length. 
The far end of this lever presses against the pin j, which in turn rests 
against the triangular plate t, to which the mirror J is held by the 
spring s. 



Fig. 57. A Four-Cylinder Manograph as It Is Rigged up Ready for Use, Indicating 
How the Four Cards Are Visible at One Time 


From this it is apparent that the engine turns the gear n, which 
rotates the gear m. This carries the pin around and thus recip¬ 
rocates the connection l and with it one end of the lever k. The 
movement of the other end of k moves the pin j, which moves the 
mirror J. The resistance of the spring s forces pin j against the end 
of lever k even when it is moving away from the pin. From the 
foregoing, it can be seen that the manograph is well adapted to 
taking diagrams from high-speed motors, for there is no limit to the 
speed of movement of the beam of light, while the error caused by 
the inertia of the few moving parts is so small as to be practically 
* negligible. 


59 





















50 


EXPLOSION MOTORS 


A view of the complete manograph, rigged up for four cylinders 
and with the engine running, indicating the four diagrams simul¬ 
taneously, is seen in Fig. 57. This gives a better idea of the device, 
its method of use, and very evident utility than anything which 
has been said on the subject. Note that the arrangement of the 
mirrors inside is such that the curves of each pair face each other, 
instead of all facing in one direction. This explains, also, the fact 
that some of the manograph curves, Figs. 66 to 70, face in different 
directions. The reader is referred forward to these diagrams, as 
showing just what is performed by the instrument described. 

To return to the slower speed or steam engine form of indicator, 
this makes a neat diagram and one which represents, within its 
speed limits, the Otto cycle taking place within the cylinders. 


IDEAL OTTO FOUR=STROKE CYCLE 

Analysis of Ideal Diagram. Watt’s work diagram may be profit¬ 
ably applied to the analysis of the ideal Otto cycle by means of the 
indicator diagram, Fig. 58. Vertical distances along the line AB rep¬ 
resent pressures in pounds per 
per square inch absolute, *while 
horizontal distances measured 
along AC represent piston 
travels or, as the cross section 
of the cylinder is constant, 
these distances may also rep¬ 
resent cylinder volumes in 
cubic inches. Thus point 4 
represents a pressure of 350 
pounds per square inch in the explosion chamber of the cylinder 
when the volume in cubic inches of this chamber is V c . 

As the line 1-2 represents the entire piston travel, any point d 
on AC represents a certain cylinder volume or marks the position 
of the piston at that point in the stroke. 

Stroke One. At the beginning of the cycle the piston is at the 
end of its path, point 1 , and is about to begin its out stroke, Fig. 59(a). 
The clearance space V c is full of products of combustion. The 

* Ab ?°! Ute Pf essur ? 3 ? re alw ays referred to zero pressure, i. e., a perfect vacuum as a 
on fheotWhand s5^ SP f T C pr f s V re ’ therefore is 14.7 pounds absoFute. Gage pressures 
gage pressure^ ’ atmospheric pressure, so that 80 pounds absolute would be 65 3 pounds 



60 

















Fig. 59. Diagrams of Various Steps in an Explosion-Motorcycle 

















































































































52 


EXPLOSION MOTORS 


pressure is atmospheric pressure (about 14.7 pounds per square inch) 
because the cylinder has been in communication with the atmosphere 
through the exhaust valve which has just closed. The conditions 
existing in the cylinder at this instant are represented in the diagram, 
Fig. 58, by the point 1, which is at a horizontal distance from the 
vertical axis, representing the clearance volume V c , also Fig. 59 (a) 
and at a vertical distance above the horizontal axis representing the 
atmospheric pressure. As the piston makes its outward stroke, the 
admission valve opens, admitting the charge to the cylinder through¬ 
out the stroke at atmospheric pressure. On the diagram the admission 
of the charge is represented by the line 1-2 , its length representing 
the volume of the charge taken in, or the distance through which the 
piston moves. The point 2 represents the condition at the end of 
the first stroke, the volume being V t , Fig. 59 (b). 

Stroke Two. The admission valve now closes and the piston 
makes its return stroke and, since all the valves are closed, the charge 
can not escape and is crowded into a smaller and smaller volume at 
increasing pressure until the piston reaches the end of its stroke, at 
which time the whole charge is compressed into the clearance space. 
This process is represented by the line 2-3, which shows the rise in 
pressure resulting from the compression. At point 3 the volume is 
again V c , Fig. 59 (c). A compression of this kind causes an 
increase not only in the pressure but also in the temperature of the 
gas, a fact often noted in the working of an ordinary bicycle pump. 
If it is assumed that during this compression the gas retains all of 
the heat formed and receives none from the outside, it is called an 
adiabatic compression. The relation between the pressure of air and 
its volume when subject to adiabatic compression is: 

PV I.40S =Constant 

In this equation P means the absolute, not the gauge pressure. 

When the charge has reached the conditions represented by the 
point 3, it is ignited and the heat generated by the explosion raises 
the temperature and consequently the pressure of the mixture. As 
the volume during the explosion will not have time to change, the 
gas will follow the general gas law, viz, that at constant volume 
the pressure P is proportional to the absolute temperature T, where 
absolute temperature is found by adding 461 to the temperature in 




EXPLOSION MOTORS 


53 


degrees Fahrenheit. The rise of pressure during the explosion is 
shown on the diagram by the line 3-4, the volume of the gas being 
constant at V c , Fig. 59 (d). 

Stroke Three. The hot products of combustion at point 4 are at a 
high pressure, consequently they now force the piston out and, expanding 
behind it, fall in pressure. This expansion is assumed to occur without 
communication of heat to or from the gas and is, therefore, an adiabatic 
expansion. It is consequently accompanied by a fall in the temperature 
of the gas, the expansion curve being shown in Fig. 58 as 4-5. This curve 
is similar to the compression curve 2-3 and has a similar equation. 

Stroke Four. At the point 5 the piston is at the end of its stroke 
and no more expansion is possible, the volume being again V 
Fig. 59 (e). The exhaust valve now opens and the pressure in the 
cylinder falls immediately to atmospheric pressure, as shown by the 
line 5-2 in the diagram, the volume remaining Vt, Fig. 59 (f). 
Throughout the last return stroke 2-1, the exhaust valve remains 
open, so that the pressure in the cylinder remains atmospheric, and 
; at point 1, the end of the cycle, the volume is again V c , Fig. 59 (g). 

Work Done by Motor. The work done by any heat engine is 
equal to the difference between the heat energy that goes to the 
engine and that which is rejected by the engine, for whatever heat 
j disappears can not have been destroyed and must have been con¬ 
verted into work. In the Otto cycle, the heat taken in is the total 
| heat which it is possible to liberate at the explosion of each charge. 
In the ideal cycle no heat is rejected from the engine except during 
the process represented by the line 5 2 in Fig. 58, because, when the 
charge gets back to the condition at 2, it has returned to its original 
volume and pressure and consequently to its original temperature. 

Thermal Efficiency. The thermal efficiency of the ideal cycle 
is the fraction of the heat supplied that is converted into work, or 
. „ (heat input)—(heat rejected) 

when expressed in ratio form, (heat input) ' 

In the theoretically ideal cycle, the thermal efficiency is calcu¬ 
lated to be from 40 to 50 per cent, depending upon the conditions 
assumed. All departures from ideal conditions result in decreasing 
the actual thermal efficiency of the motor. This efficiency is always 
less than that of the ideal cycle, usually being only from 50 to 60 
per cent as great. 





54 EXPLOSION MOTORS 

OTTO FOUR=STROKE CYCLE IN PRACTICE 
General Analysis 

In the discussion of the ideal Otto cycle we assumed that the 
compression and expansion curves were adiabatic and that the walls 
surrounding the combustion chamber were impermeable to heat. 
We also assumed perfect and instantaneous ignition, that we had a 
charge of uniform composition possessing all the physical properties j 
of air, and that combustion was complete. None of these assump¬ 
tions are quite true in practice and each variation from the ideal ; 
condition has its influence upon the performance of the motor. In j 
addition to the above, we did not consider the loss due to the 
necessary cooling of the cylinder. In fact, the water jacket around 
the cylinder (this applies to air cooling as well), without which the 
cylinder would be too hot to be properly lubricated, is the main cause I 



Fig. 60. Indicator Card of a Motor Following Actual Otto Cycle 


of the difference between the real and ideal cycles, as the cooling 
agent absorbs about 40 per cent of the total heat of combustion. 

In order to analyze the differences between the ideal and the 
actual or practical cycles, let us compare Fig. 58 with Figs. 60 and 
61, which represent, respectively, the cards of a motor which is 
supposed to follow the actual Otto cycle, and of a four-cycle gasoline 
engine as found in practice. 

Suction Stroke. At the end of the exhaust stroke, the clearance 
volume V c , Fig. 60, is filled with burned gases at a pressure P e 
and temperature T e . Nothing definite is known of the temperature 
T e , except that it varies from 1,200 to 1,800 degrees Fahrenheit, 
while P e ranges from 16 to 18 pounds absolute pressure per square 
inch. At the beginning of the suction stroke the pressure decreases 


64 














EXPLOSION MOTORS 


55 


from P e to the suction pressure P 2 along the curve determined by 
the re-expansion of the burned gases in the clearance space. This 
is the curve shown at A. The fresh charge can not be drawn into 
the cylinder until after this re-expansion of the burned gases. 
Anything—such as a badly formed exhaust port, restricted exhaust 
passage, or a too early closure of the exhaust valve—which may give 
us too high an exhaust pressure or too large a volume of exhaust 
gases remaining behind, will decrease the cylinder capacity and 



Fig. 61. Indicator Card of Four-Cycle Explosion Motor 


hence materially reduce the efficiency of the cycle. The dotted line 
curves near A show how the above would affect the card. 

Scavenging. If by any means we can reduce the effect of the 
clearance exhaust, we would increase the efficiency. This is actually 
accomplished by what is termed scavenging. Since the exhaust gases 
which occupy the clearance space are usually at a high temperature 
T e , their mixture with the entering charge heats it, decreasing 
its density and, therefore, its amount. Consequently, it is very 
essential that these exhaust gases be excluded from the cylinder 
before the fresh charge enters. This clearing-out or scavenging of 
the cylinder with fresh air has been accomplished in several ways. 
The simplest method is by the use of an exhaust pipe of such length 
that the gases, exhausting from the cylinder with great velocity, 


65 






























56 


EXPLOSION MOTORS 


create a vacuum in the cylinder near the end of the exhaust stroke. 
This vacuum causes the automatic air-admission valve to open; and 
the consequent rush of air from the air-valve to the exhaust port 
flushes out the cylinder, especially if the air and exhaust valves are 
on opposite sides of the clearance space. Scavenging may also be 
accomplished by pumping air through the clearance space. 

Suction Pressure. Another factor affecting the efficiency is the 
suction pressure P 2 , Fig. 60. Owing to friction losses in the admis¬ 
sion valves and pipes through which the fuel enters, the admission 
pressure is less than atmospheric pressure, 12 \ pounds per square 
inch absolute being the average value for P 2 in this type of motor. 
Owing to this reduction in pressure, the charge, if it were brought 
to atmospheric pressure, would occupy a volume V' s instead of V s , 
Fig. 60. This reduction in the amount of the charge, of course, • 
decreases the pressure developed at the end of the compression 
stroke and, therefore, reduces the heat developed by the explosion, 
which reduces the power developed within a given size of motor. ; 
Hence, the smaller the suction pressure, the less power we get, and 
the closer P 2 is kept to atmospheric pressure the greater will be the ' 
possible power output. We thus see that modifications occur at \ 
each end of the suction line which tend to decrease the efficiency of 
the cycle. This effect produced by the reduction of P 2 permits the ] 
motor to be governed by means of a throttle valve. P 2 is increased j 
or decreased as required by the use of a control valve whose suction 
responds to the load on the engine, thus controlling the charge 
Volume and hence the engine capacity. 

The temperature U of the charge has been found by experiment 
to be between 200 and 300 degrees Fahrenheit. 

Compression Stroke. The compression is not adiabatic because 
it occurs in a cast-iron cylinder, which takes heat from the gas while 
it is being compressed and so makes the final temperature and 
pressure less than those calculated on the assumption of adiabatic 
compression. In general, however, the compression curve may be 
considered in actual practice to follow the general gas law. During 
the first part of the stroke the charge receives heat from the walls, 
but due to the heat generated by compression, this is soon over¬ 
balanced and during the last and greater part of the stroke the charge 
loses heat to the walls. As a result of this the compression curve is 


66 


EXPLOSION MOTORS 


57 


found to be between an adiabatic and an isothermal.* As a result of 
this exchange of heat, first from the walls and then to them, the expo¬ 
nent n in the general gas law equation P V n — Constant is not constant 
along the entire curve. In actual practice n is found to average about 

(1+ c ) 1 - 35 

1.35. We thus have in the actual cycle, P 3 = 12.5 - 


P 3 = 14.7 


(1+c) 


instead of 


for the ideal cycle, where c is the percentage 


of clearance. (See page 58 and Table I.) The less effective the 
cooling, the greater will be the value of n. Any leaks past the piston 
or in the valves will result in a flattened compression curve which 
results in a decrease in the value of n . 

Theoretically an increase in compression pressure P 3 will give 
an increase in efficiency. Practically this is true only up to a certain 
point. 

The amount of compression that can be used is limited in two 
ways. First, it is not commercially practicable to construct motors 
which will work properly under very high pressures rapidly imposed 
by explosion. With an engine compressing a charge to 100 pounds 
and using a strong explosive mixture, the pressure in the cylinder 
rises suddenly to about 350 pounds and this is at present about the 
practical limit. If the explosive mixture is very weak, the compres¬ 
sion may be increased as high as 200 pounds, resulting in a maxi¬ 
mum pressure of about 300 pounds. 

• The second objection to the use of high compression is that the 
rise in temperature of the mixture resulting from the compression 
may easily be sufficient to explode the mixture before the piston has 
reached the end of its stroke. Such pre-ignition of the charge tends 
to force the piston back, giving rise to a great shock, which is not 
only very destructive to the engine but reduces its efficiency and 
consequently should be avoided. Pre-ignition may occur even with 
low compression, if any part of the clearance is not water jacketed, 
or properly air-cooled, or if there is any metallic projection in the 
clearance space. Lucke states that compression pressures of from 


♦Adiabatic compression, as already stated, is one in which all the heat resulting from 
the compression is retained in the gas compressed; in an isothermal compression, the heat is 
a * *Ai r nroduced. In this case some of the resultant heat is retained and 

someTof itfs^ost; therefore, the curve partakes of the properties of both adiabatic and isother¬ 
mal lines and is found to lie between the two. 


67 







58 


EXPLOSION MOTORS 


TABLE I 


Effects of Clearance 


Percentage Clearance 
of Otto Cycle 
Engine 

Pressure at End of 
Compression 

Lbs. per Sq. In. 

Efficiency of Otto 
Cycle 

Efficiency of Cycle 
with Increased Ex¬ 
pansion, but with 
Same Compression 
Pressure as Otto 
Cycle. 

20 

183.3 

51.6 

60.9 

25 

141.1 

47.9 

58.4 

30 

115.4 

44.8 

55.0 

35 

98.0 

42.1 

52.5 

40 

85.5 

39.8 

50.4 


45 to 95 pounds per square inch are safe as regards the danger of 
pre-ignition in the type of motor under consideration. 

Effects of Clearance. The efficiency of an engine depends not 
at all upon the temperature and the pressure at the end of the explo¬ 
sion, but only upon the ratio of the temperatures at the beginning 
and at the end of the compression. Since this ratio in turn depends 
only upon the ratio of compression, and since, further, the charge 
is always compressed till it occupies the clearance volume, the effi¬ 
ciency is seen to depend only upon the percentage of clearance. In 
other words, in engines using the same gas and following the Otto 
cycle, with the same percentage clearance, the percentage of the 
heat liberated in the cylinder that is converted into work is always 
the same, whatever be the size of the engine or the strength of the 
charge. The effect of the clearance on the efficiency is exhibited 
in Table I, where it is seen that the smaller the clearance the 
greater is the efficiency of the engine. The pressures at the end 
of compression are also given in the table, and are calculated on 
the assumption that the atmospheric pressure is 14.7 pounds per 
square inch absolute. 

Explosion. The shape taken on the indicator diagram by the 1 
line representing the explosion of the charge depends mainly upon the 
inter-relation of three things, viz, the particular composition of the 
charge, the ignition point, and the piston speed. 

For each power of engine there is a certain relation between 
the proportions of air and vapor in the mixture which will give the 


68 








EXPLOSION MOTORS 


59 


most rapid combustion. Any increase in the amount of air or burned 
gases contained in the charge will result in a lowering of the rate of 
combustion until a point is reached where the mixture will no longer 




Fig. 62. Cards Showing Varying Rates of Combustion 


explode. In Fig. 62, A is a diagram of a motor with throttle full 
open, speed constant, and proper ignition; B shows the conditions 
of the same engine after partly closing the throttle, thus increasing 
the proportion of burned gases contained in the charge; and C shows 
the conditions on further closing the throttle. Similar diagrams 
would have been obtained had the throttle been left full open and 
the proportion of air in the first charge considerably increased in 
B and C. A vertical or nearly vertical explosion line such as that in 
A indicates proper combustion. The more slanting the explosion 
line, the poorer the ignition. Referring to C, it is readily seen that 
the maximum pressure of the explosion does not begin to act on the 
piston until the piston has traveled a considerable distance out on 
the power stroke. 

From the above, it will be seen that for each different fuel 
mixture and each different piston speed there will be a different point 

of ignition if we are to 
secure maximum results. 
This shows that it is ad¬ 
visable that each motor 
have adjustable ignition ap¬ 
paratus, because the only 
way to determine a proper 
time is by actual trial. Fig. 
63 shows a set of diagrams 
given by Clerk which illus¬ 
trates the results of improperly timed ignition. A is the normal 
diagram with proper ignition, while B, C, and D show what occurs as 



Fig. 63. 


Card Showing Results of Varying 
Time of Ignition 


69 
















60 


EXPLOSION MOTORS 


the ignition is made later and later. With the time of ignition remain¬ 
ing constant, successive increases in piston speed would have given 
diagrams similar to those of Fig. 63. The maximum pressure reached 
during combustion depends upon the heating value of the charge 
and should be reached at or before one-tenth stroke. The pressure 
n+ . maximum pressure 

ratl0 > - ; 1 usually has a value of between 3 and 

compression pressure 

5, for gasoline. 

The maximum explosion pressure (see point 4, Fig. 60), even 
with proper ignition is never as high for the actual cycle as for the 
ideal cycle. The principal reason advanced for this is the loss of 
heat to the water jacket, or air, if air-cooled, this loss amounting to 
usually about 40 per cent of the total heat of combustion, i. e., heat 
which results from the explosion of the charge. Some of the other 




Fig. 65. Card Showing Case of 
Back-Firing 


reasons are the rise in specific heat* of the gases with rise in tempera¬ 
ture, and the fact that perhaps not all of the heat of the charge is 
liberated when the piston starts forward, which results in after 
burning. 

Fig. 61 shows the card actually taken from a gasoline engine 
as given by Lucke. The engine had a compression of 80 pounds 
and a maximum pressure of 372 pounds. Fig. 64 shows the results 
of pre-ignition, the card clearly indicating that the explosion has 
occured before the end of the compression stroke and that considerable 
of the stored-up energy of the engine is spent in overcoming the maxi¬ 
mum force of the explosion. This results in this particular case in 
cutting the power of the engine nearly in half. 


- o I ^Specific heat of a substance is the ratio of the heat required to raise the temperature 
theYaS“wefeht rf water^^om ef<- toePA" ’ ‘° ““** reqUiled *° raise the of 










EXPLOSION MOTORS 


61 


Fig. 65 shows the difference between a case of back-firing and 
the case of pre-ignition shown in Fig. 64. The explosion occurs in 
the suction pipe during the suction stroke. Back-firing, however, is 
more apt to occur in the exhaust pipe than in the suction pipe. 

Power Stroke. The curve of expansion in the actual cycle 
follows the general law and, because of the loss of heat through 
the cylinder walls, should lie below the adiabatic curve. In prac¬ 
tice, however, it is found that it does not fall off as quickly as expected, 
sometimes coinciding with the adiabatic, but usually being found 
between this and the isothermal. An evolution of heat along the 
expansion curve is supposed to be the cause of this. A great many 
theories have been advanced to explain this, nearly all trying to 
prove that, owing to certain reasons, after-burning takes place. 
However, up to the present time no really satisfactory explanation 
I has been advanced. A value of 1.35 is a fair average value for n, 

! thus making the general equation PF 1,35 = Constant. 

Exhaust Stroke. At the instant the exhaust begins, the velocity 
of efflux of the burned charge is from 2,500 to 3,500 feet per second. 
The exhaust valve should start to open at about one-tenth before 
; the end of the stroke. The port should be so proportioned that 
i the pressure has been equalized by the time the outer dead center 
j is reached. If this is not the case there will be an increase in the 
: work lost, due to higher back pressure, higher mean cylinder tem- 
[ peratures, and smaller cylinder capacity. In actual practice the 
pressure at the beginning of the exhaust stroke has been found in 
many cases to average about 25 pounds per square inch. 

The movement of the burned gases out through the exhaust 
pipe is resisted by friction in the various parts. These gases are 
forced out against atmospheric pressure, hence the pressure inside 
the cylinder which expels them must be above atmospheric pressure. 
This pressure is maintained by the piston which follows up the 
i retreating gases. The difference in pressure between that inside 
the cylinder and that outside, i. e., the exhaust pressure and the 
atmospheric pressure, respectively, opposes the motion of the piston 
on the exhaust stroke and hence causes a loss. This loss is clearly 
shown in Fig. 60 by the fact that the exhaust line on the indicator 
card is above the atmospheric line, thus decreasing the area of the 
card which is proportional to the amount of work done. 


71 







62 


EXPLOSION MOTORS 


Modifications for Modern Motors 

Large Valve Ports. In modern motors, it has been found 
possible to modify the actual indicator card and the output of the 
engine very materially by slight modifications in the parts and their 
arrangement, as just pointed out. Thus, relative to drawing in the 
fresh charge of gas, after the exhausting has been nearly completed, 
it has been found that larger exhaust valves and ports would carry 
out the burned gases quicker and more completely, so as to leave a 
cleaner cylinder for the fresh charge to enter. 

Similarly, larger inlet valves and ports have been found to 
give a quicker and more complete inflow of fresh charge. The two 
items combined—better scavenging and a more complete charge 
of purer gas—have had a material influence upon the efficiency. 
In the same way, larger intake ports and valves have operated to 
increase the suction pressure. As has been pointed out, this influ¬ 
ences the pressure at the end of compression, and, therefore, the heat 
developed by the explosion, and ultimately the power developed. 
Thus, larger valves and ports producing increased suction pressure 
have increased the power output. This tendency has been carried 
up to the point where the diameter of the clear valve opening has 
been as close to one-half the cylinder diameter as was practicable, 
that is to say, a motor of four-inch bore nowadays would have 
valves with a clear opening of approximately lH-inch diameter, 
or just ^ inch below half the cylinder diameter. 

Exhaust Gas Friction. Also the exhaust gas friction pro¬ 
duced by the pipes has been made an almost negligible quantity 
by making the pipes of much larger diameter, with fewer and easier 
bends, while larger mufflers of better design have tended to give 
a greater vacuum. With all these influences at work, it has been 
found possible to increase the speed of exhaust gases. Several 
recent motor designs have an important departure in that the 
the exhaust pipe, instead of turning directly toward the rear, has 
been carried forward in a long, easy bend, coming as close to the 
rear of the radiator as possible and then passing beneath the engine 
supports to the muffler at the rear. The close proximity of the 
exhaust pipe to the radiator and the cold air flowing through it 
have produced an internal cooling and condensing effect which has i 
increased the vacuum pressure in the exhaust system and in this 


EXPLOSION MOTORS 


63 


way has produced superior and more complete scavenging, which 
always results in greater power. 

In some six-cylinder motors and all in the eight-cylinder forms 
now being produced, a similar result has been attained by using 
double sets of exhaust pipes, leading to a pair of distinct mufflers on 
opposite sides of the chassis or else to one unusually large one. In 
the case of the six-cylinder engines, usually the first three cylinders 
have been considered as one group with their own exhaust pipe and 
muffler, while the rear three formed the other group. In the case 
of eight-cylinder V-types, the right-hand group formed one unit 
for exhausting purposes, and the left-hand lot of cylinders the 
other. 

Effect of Large Ports on Silence of Motor. While it has no bear¬ 
ing upon the subject under discussion, this seems a good place to 
mention the fact that anything tending to make more complete, 
j easier, and quicker any natural function of the motor, as the 
i inflow of fresh gas, the outflow of burned gases, etc., also tends to 
j increase its silence, as well as to increase its volumetric efficiency. 
\ This combination, with the demand for more economical motor cars, 

| has brought about the high-speed small-bore motor of today. To 
;make this statement more pointed, it should be said that motors 
| are now being constructed and sold in many popular types of car, 
which have a bore one inch less than it was considered practicable 
to build five years ago. 

Manograph Cards. Before turning to the two-cycle form of 
motor and the diagrams, both theoretical and actual, it will be well 
i to look at some manograph cards in order to see just what kind of 
I cards the manograph makes and how they compare with those made 
I by the steam-engine form of indicator. 

In Fig. 66 is presented what might be called a good card. This 
| was taken from a motor of 120-millimeter bore (4.72 inches, in 
! round figures, 4f) by 130-millimeter stroke (5| inches), running 
I at about 1,100 r. p. m. As will be seen at once, this is a combina- 
jtion of a number of successive diagrams, superimposed. The line 
DB indicates excellent admission, with a slight rise near the end 
of the line, showing a slight increase in pressure due to the inertia 
of the inflowing gases. Then BF shows a good compression line, 
indicating that the amount of gas admitted has been good, that is, 


73 



64 


EXPLOSION MOTORS 



that admission had been complete. Next, the vertical line from F 
upward indicates a first-rate explosion. 

From the maximum explosion point down to A, the curve 
indicates the expansion. At E will be seen the variation in the 
successive cards, all of them good but varying slightly from one to 
another as a better or more complete charge was drawn in, a slightly 
higher compression pressure obtained, a better or hotter spark 
produced, or according to other conditions in the cycle. The sharp 


Fig. 66. A Good Manograph Card from a Medium-Sized Four-Cylinder 
Motor, Showing How a Large Number of Cards Are Taken at Once 

end of the expansion curve at A, which indicates the opening of the 
exhaust valve, is very good, as is also the line from A to D and the 
end of the exhaust stroke. Near the end of this it will be noted 
that the exhaust line goes below the intake line, indicating a slight 
vacuum in the exhaust system. 

Fig. 67 shows another card taken from the same engine but at 
a reduced speed, which was being lessened further as the card was >j 
taken. The mixture was good, and the charge very complete, while I 


74 









EXPLOSION MOTORS 


65 


m 



the slower speed allowed of a better mixing of gas, a superior diffu¬ 
sion of the gases in the cylinder, and a better explosion. The lower 
pressures of admission and exhaust do not show up as plainly, but 
the explosion line above F is very marked. The agitation 
the gaseous mixture is plainly 
shown in the several waves 
of the first part of the ex¬ 
pansion curve at E. Sim¬ 
ilarly, a good free exhaust is 
indicated from A to the base 
line and to the end of the 
stroke at D. 

Fig. 68 points out the 
evil results of retarded spark, 
this curve indicating the 
loss of power due to this 
cause. Note that from F 
upward the curve is not 
vertical as in the preceding 
diagrams but slopes off to the left. This, of course, indicates a 
loss of power. Note also the poor expansion curve from E down¬ 
ward, and the comparatively poor exhaust, starting too early and 
continuing too long and too slowly, as indicated by the length and 
slope of the curve around A. 

The diagram at Fig. 69 
indicates poor compression. 

This may be caused by leak¬ 
ing piston rings, a piston or 
cylinder which has worn 
oval, too small or restricted 
inlet ports or valves, and a 
number of other things. The 
curve BC represents the in¬ 
take, in which it' will be 

noted first that it starts higher than usual, the upturn at B 
indicating that the exhaust closes too soon, leaving gases under 
pressure in the cylinder. The droop in this line indicates the 
remarkably poor suction, which is followed by the line CDE, indi- 



Fig. 68. A Manograph Card from the Same Motor, 
Indicating the Disadvantages and Results 
from Over-Retarded Spark 











66 


EXPLOSION MOTORS 


eating the compression and expansion, while EFA indicates the 
expansion and beginning of the exhaust. It will be noted that all of 
these are poor, the fact of the expansion line being below the compres¬ 
sion line indicating negative 
work, that is, this shows that 
more power was required to 
compress the gases than they 
gave out during their ex¬ 
plosion and subsequent ex¬ 
pansion. The exhaust line 
AB is fairly good, excepting 
only the early closing as 
previously pointed out, indi¬ 
cating that the trouble here 
lies mainly in the suction 
(carburetion system), com¬ 
pression, and expansion (cyl¬ 
inder construction and condition), with incidentally a poor spark 
(ignition system). 

Finally, Fig. 70 shows a diagram taken from an engine with 
a suction inlet valve. This form is no longer used for automobile 
engines, but is of interest because it indicates that this form of 
valve had a considerable influence on the power of the motor. It 

will be noted that the inertia 
of the valve was considera¬ 
ble, and the suction not suffi¬ 
cient to hold it wide open 
all of the time. This can 
be noted in the waves of the 
admission curve. Its influ¬ 
ence on the power can be 
seen in the poor explosion 
line, following a very good 
compression curve, and this 
in turn, followed by but 
a fair expansion. Finally, there is shown a poor exhaust, as indi¬ 
cated by the rising straight line. This means increasing pressure as 
exhausting proceeded, whereas it should show a drop, if anything. 




Fig. 69. A Manograph Card Indicating Remarkably 
Poor Compression and What It Produces 
in the Cycle 














EXPLOSION MOTORS 


67 


TWO-CYCLE MOTOR DIAGRAM 

The compression, explosion, and expansion lines of the indicator 
diagram are the same for the two-cycle as for the four-cycle motor, 
the only difference between the two types being in the way the 
exhaust and charging actions are carried on. In Fig. 71 is shown 
the indicator diagram of a motor which exactly follows the ideal 
two-stroke cycle. The exhaust opens at A, the burned gases escape, 
the intaking of the charge commences and is completed at B, where 
compression commences. From the above it is seen that the exhaust 
and intake actions must be done during the time that the piston 
moves from A to the end of the stroke C, and back again to B. 

Admission of Charge. The very short interval of time between 
the beginning of the exhaust and the admission of the new charge 
(which enters as soon as the pressure in the cylinder has fallen 
enough to permit the admission valve to open) makes premature 
ignition of the charge, or back-firing, of not infrequent occurrence. 
If the mixture is weak, or the 
speed is very high, so that 
the charge is still burning 
when admission begins, or if 
the frequency of the explo¬ 
sions brings any part of the 
cylinder to a red heat, the 
charge will be ignited on 
entering, and the explosion then travels back to the crank case, 
which has to be made strong enough to resist it. 

In all explosion motors a certain amount of work has to be done 
in getting the explosive mixture into the cylinder during the suction 
stroke, and in expelling the exhaust gases during the exhaust stroke. 
This gas-friction work is represented on the indicator card of an Otto 
cycle motor by the negative loop, Fig. 72, which has to be subtracted 
from the positive loop in order to give the indicated horse-power of 
the motor. In the four-cycle motor this negative work is usually 
from 2 to 5 per cent of the total work, and is a dead loss. In the 
two-cycle motor, considerably more work must be done in order to 
get the gas into the cylinder. The time available for the admission 
of the charge is extremely short. In a small high-speed motor, it 
will be from one- to two-hundredths of a second; in a large two- 





68 


EXPLOSION MOTORS 


cycle motor, it may amount to one-twentieth of a second. In any 
case it will not be more than one-third to one-fifth of the time avail¬ 
able for admission in a four-cycle motor. 

Pre-Compression. In order to overcome the back-pressure of 
the exhaust, and also in order to be able to enter with the very high 
velocity necessitated by the short duration of admission, the explosive 
mixture has to be pre-compressed to 8 or 10 pounds above atmospheric 
pressure before its admission to the cylinder. Whether this pre¬ 
compression is done in the crank case, as in small motors, or in sepa¬ 
rate compression pumps, as in large engines, it requires the expendi- 



ADM/SS/ON 
COMPRE SS/ON 
EXPANS/ON 
EXHAUST 


1ST STROKE 
ZHD. STROKE 
3RD. STROKE 
4TH. STROKE 


)• 1ST REVOLUTION 

\rhd. revolution 


Fig. 72. Diagram Showing Operations of Four-Stroke Cycle. Lower Part of Diagram, 
Called the Negative Loop, near Atmosphere, Exaggerated 

tare of a considerable amount of work—an expenditure which 
decreases the available power of the motor without giving anything 
in return other than the possibility of maintaining the cycle of 
operations. This loss of power in compressing the charge is ordi¬ 
narily from 15 to 20 per cent of the total work done in the cylinder. 

Valve Timing. Another loss of efficiency in the two-cycle 
motor results from the fact that the admission and exhaust ports 
are open at the same time. An endeavor is made to have the exhaust 
port close before any of the entering charge has reached it; but it 
is not practically possible to accomplish that—particularly in a 
motor which is to run at various speeds. If, in an endeavor to 
# prevent such loss of charge direct to the exhaust, the exhaust port 















EXPLOSION MOTORS 


69 


closes early, too large a volume of the exhaust gases will be retained 
in the cylinder; the amount of the charge which can enter will be 
correspondingly decreased; and both the efficiency and the capacity 
of the motor will suffer. In large engines, this trouble is to a great 
extent obviated by forcing air into the cylinder slightly ahead of 
the explosive charge, and closing the exhaust port when the charge 
of fresh air is passing through. This device is also valuable in 
preventing back-firing of the charge. 

Scavenging. The success of the two-cycle operation depends 
primarily upon how thorough the scavenging action is carried out, 
since upon this depends the explosibility of the charge, as well as 
its volume, which in turn determine whether the engine runs at all, 
and if so what its efficiency will be. 

For successful action, point A, Fig. 71, should be at atmos¬ 
pheric pressure, any increase above that given tending to increase 
the volume of exhaust gases remaining in the cylinder as well as 
the work done by the piston during exhaust. Practice has shown 
that scavenging, in order to be thorough, must be commenced 
somewhere between A and C. 

Throttling. The power of a small two-cycle motor can be varied 
by throttling, that is, by varying the amount of the charge taken into 
the cylinder. This is accomplished either by throttling the admission 
to the crank case, or else by throttling in the by-pass between the 
crank case and the cylinder. There is probably but little to choose 
between these two methods. 

Reversibility. Besides its simplicity and compactness, the two- 
cycle motor may claim reversibility as one of its advantages. The 
direction of rotation in the valveless two-cycle motor is determined 
solely by the timing of the ignition. It is possible to reverse such 
a motor merely by making the point of ignition very early. This 
causes an explosion well before the ending of the compression stroke 
and may develop sufficient pressure to stop the piston before it gets 
to the end of the stroke and start it going in the other direction. 
When once started in the other direction, the ignition, if unchanged, 
will be a very late ignition, giving comparatively small power; shifting 
the ignition back a little will give the motor its full power in its re¬ 
versed direction. This process is practicable only in motors with light 
reciprocating parts; it is most convenient for small motorboat use. 


79 




70 


EXPLOSION MOTORS 


Summary. In theory, the two-cycle motor develops about 65 
per cent more power than a four-cycle motor of the same size and 
speed; it uses from 10 to 20 per cent more gas per brake horse-power. 
In actual practice, however, it has been difficult for two-cycle 
designers and advocates to show more than 10 per cent increase for 
equal size, while the two-cycle form cannot produce as low a mini¬ 
mum nor as high a maximum speed. The latter has a large influ¬ 
ence on the power output, as the four-cycle engine develops the 
greater part of its power at the upper or high speed end of the power 
curve. Consequently, the maximum output of a four-cycle motor 
has always been greater than that of a two-cycle motor of equal size 
because of the greater speed possibilities of the former. Moreover, 
the majority of car manufacturers and independent designers have, 
in the past six or eight years, worked on the four-cycle form with 
the result that it has approached a high state of perfection. The 
same can not be said of the two-cycle motor. 

Except for the above-mentioned differences and the difference 
in the form of the diagram, as has just been pointed out, the ther¬ 
modynamics of any two-cycle type of motor is exactly the same as 
that on any four-cycle type. 

FUELS 

Explosion motors can be made to work with any explosive 
mixture, those of air with gaseous fuels being naturally the mixtures 
most easily made and controlled. Mixtures of air with liquid fuels 
offer generally no particular difficulty, but those with solid fuels 
(such as powdered coal), although they have been tried, are not 
practicable on account of the ash which remains in the cylinder and 
rapidly abrades it. The single exception to the above statement is 
naphthalene. As will be described later, this is a solid fuel which 
has been converted first to a liquid and then to a gas, with very 
great success abroad, and at a surprisingly low cost. A number of 
French and English commercial vehicles are now being operated 
upon it. Mixtures of two different kinds of liquid fuels, and of a 
solid and a liquid fuel have generally been successful where the two 
components were carefully chosen as to their suitability. As an 
example of this last statement, kerosene and gasoline mixtures will 
operate successfully where kerosene alone can not. Many drivers 


EXPLOSION MOTORS 


71 


economize on their fuel bills in this way, adding kerosene in quan¬ 
tities up to 40 per cent of the total to their gasoline. Similarly, 
with gasoline and alcohol, kerosene and alcohol, naphthalene in 
gasoline or kerosene (when the fuel is preheated), and others. 

Table II gives the heat values for most of the commercially 
available fuel materials for explosion motors. 

The liquid fuels are the only ones with which we are concerned, 
and of these gasoline is by far the most important, since it is the 
one almost exclusively used in the motors which we are considering. 

Petroleum Products. Crude petroleum furnishes us the follow¬ 
ing commercial products for power purposes: Gasoline, naphtha, 
kerosene, gas oil, and crude oil. 

These products are separated from the crude petroleum by distil¬ 
lation, i. e., the crude petroleum is heated and its various products 
are given off as vapors; the lightest or most volatile product is 
given off first, then as the temperature is raised still higher, the 
next most volatile ingredient is given off, and so on through the 
entire list. 

Rhigolene, sp. gr.* 0.60, distills off at 113° F.; cymogene, sp. gr. 
0.625, at 122° F.; gasoline, sp. gr. 0.636 to 0.657, at from 140° to 
158° F.; C. Naphtha, sometimes called benzine, sp. gr. 0.66 to 0.70, 
at from 158° to 216° F.; B. Naphtha, sp. gr. 0.71 to 0.72, at from 
216° to 250° F.; A. Naphtha, sp. gr. 0.72 to 0.74, at from 250° to 
300° F. Various authorities differ concerning these values, but the 
ones here given are safe average figures. 

Gasoline. What we in America know as gasoline is really a 
combination of the above fractional distillates whose specific gravity 
runs from 0.63 to 0.74|. The boiling point of gasoline such as is 
usually used in explosion motors ranges from 150° to 180° F., and 

♦Specific gravity. 

fSpecific gravity is figured in two ways, one a decimal quantity and the other an arbitrary 
figure, as determined on the scale of an instrument known as a Baume hydrometer. The latter 
figures are called degrees Baum A This quantity is used in America more than the actual specific 
gravity, although the former is usually spoken of as the specific gravity. The increase in weight 
of the usual fuels, as we pass from the lighter gasoline up to kerosene, and beyond that to heavier 
forms, would be reflected by the specific gravity. As everyone knows, however, we speak of 
gasoline as getting poorer, now we get but 56 whereas we used to get 76, etc. These figures refer 
to the Baume scale, which gives a lower reading for a heavier liquid. Thus specific gravity may 
be figured from degrees Baume by adding the Baume reading to 130, and then dividing 140 
by the result, or „ 

140 

Specific Gravity = --- 

130 + Baumd 

Using this on the figures given above, we find that 56 Baum6 equals .75 s. g. and 76 Baumd, .68 
s. g. The remark then translated into actual specific gravity would read, now we get .75 gas- 
oline, whereas we used to get .68. This is correct, for present-day fuel is heavier than that of 


81 






72 


EXPLOSION MOTORS 


TABLE II 


Explosion Motor Fuels 


Gases, Vapors, Liquids, and Solids 

Heat Units* 
per Pound 

Heat Units 
per Cubic Foot 

Hydrogen 

61,560 

293.5 

Carbon 

14,540 


Crude Petroleum 

18,360 


Kerosene 

22,000 


Benzine 

18,450 


Gasoline 

18,000 


Alcohol, Methyl 

20,000 


Denatured Ethyl Alcohol 

13,000 


Acetylene 

21,490 

868 

19-can. power Illuminating Gas 


800 

16-can. power Illuminating Gas 


665 

15-can. power Illuminating Gas 


620 

Gasoline Vapor 

18,000 

692 

Natural Gas, Leechburg, Pa. 


1050 

Natural Gas, Pittsburg, Pa. 


890 

Water-Gas 


290 

Producer-Gas 


150 

Suction-Gas 


135 


*A heat unit or British thermal unit (B. T. U.) is, practically speaking, the quantity of 
heat required to raise the temperature of one pound of water one degree Fahrenheit. 


the flashing pointt of the liquid ranges from 10° to 14° F. A mix¬ 
ture of one part of this gasoline vapor to 7.3 parts of air produces 
what is theoretically a perfect combustion mixture. A decrease in 
the proportion of air may leave, as a residue in the exhaust, uncon¬ 
sumed vapor, while an excess of air up to a limit of 10 parts of air to 
1 part of vapor may increase the fuel efficiency. As a matter of 
fact, the modern automobile engine will operate on any mixture 
between 5 to 1 and 15 to 1. 

A sample of gasoline of specific gravity 0.71 showed 83.8 per 
cent carbon, 15.5 per cent hydrogen, and 0.7 per cent impurities, 
and had a heating value of 18,000 B. T. U’s per pound. The various 
grades of gasoline differ mostly by the percentage of hydrogen 

five years ago. By referring to the s. g. of kerosene, it can be figured out readily that the actual 
case is that fuel now sold as gasoline contains a considerable amount of what was formerly sold 
separately as kerosene. Except for the name this is no disadvantage, but on the contrary an 
advantage so long as the carbureter will handle it, for kerosene contains a greater number of 
heat units per pound. 

$The flashing point of a substance is the lowest temperature at which it gives off vapor 
in sufficient amount to form with the surrounding air a mixture which is capable of burning when 
ignited. 












EXPLOSION MOTORS 


73 


contained. A gallon of liquid gasoline will in the form of a vapor 
fill about 160 cubic feet, or about 1,200 times its liquid bulk. Gaso¬ 
line of 0.74 specific gravity will weigh 6.16 pounds per gallon, and its 
pure vapor, which occupies about 26 cubic feet per pound, has a 
heating value of 690 B. T. U’s per cubic foot. 

Kerosene. Kerosene is distilled from crude petroleum at a, 
temperature of from 300° to 500° F. Its specific gravity is from 
0.76 to 0.80. 

Coal Gas. Coal gas has a specific gravity of 0.80, given off 
above 560° F. Crude oil is what remains after the above distillation 
process. 

Miscellaneous Distillates. The former simple division of crude 
petroleum products into four parts, gasoline, kerosene, coal gas, 
and crude oil, is no longer correct. The tremendous demand for 
motorcar and boat fuels has brought about the need for a larger 
percentage of gasoline, which has been supplied by making it heavier 
through the inclusioi of much of what was formerly sold as kero¬ 
sene. To keep up the quantity of the latter, this too has been 
made heavier by the inclusion of considerable quantities of what 
formerly was distilled over as coal gas. In addition, the distillation 
! is further split up by the separation of the naphthas, first the lighter 
| benzine naphtha, then naphtha, then benzine. Finally, what was 
formerly lumped as crude oil remainder is now split up into a number 
of different oils, with the final remainder, now called “residuum” or 
“tailings”. The latter is sometimes fluid, but more often a viscous 
! semi-solid dark-green or dark-brown substance with an unpleasant 
i odor. As a matter of fact, several carbureters have been developed 
on the Pacific Coast, by means of which this former waste material 
- Can be first liquefied, then converted into a gas and burned in motor 
truck engines. When this is done, an important economy is effected, 
for this material sells for about three cents a gallon, and in some 
localities as low as 1 \ cents, when sold in barrel lots. 

Denatured Alcohol. There are two kinds of alcohol, viz, (1) 
j ethyl alcohol (C 2 H 6 0), which can be made from corn, rye, rice, 
molasses, beets, or potatoes, by a process of fermentation and distil¬ 
lation; and (2) methyl or wood alcohol (CH 4 0), which is obtained 
from the destructive distillation of wood. Ethyl alcohol is that 
which is present in alcoholic beverages; wood alcohol is a virulent 


83 



74' 


EXPLOSION MOTORS 


poison. Denatured alcohol is ethyl alcohol which has been rendered 
unpalatable and unfit for consumption by the addition of wood 
alcohol and a little benzine or other substance. It gives up about 
11,800 B. T. IPs per pound on burning; consequently it does not 
give up much more than one-half as much heat per pound as gaso¬ 
line or kerosene. The weight and volume of denatured alcohol 
required to develop a given power in a motor is considerably greater 
than the amount of gasoline for the same power; and, therefore, if 
a gasoline motor is to be used with alcohol, the orifices in the car¬ 
bureter or other spraying device have to be enlarged so as to admit 
a greater volume of the liquid. Wood alcohol can not be used by 
itself in a motor, as it corrodes the cylinder. Denatured alcohol, 
in its volatility, lies between gasoline and kerosene, the amount of 
vapor which it gives off to air that passes over it being generally 
sufficient to give an explosive mixture, if the temperature of the air 
and alcohol are above 70° F. With an ordinary spray carbureter 
a considerable excess of alcohol may be sent to the cylinders, as such 
carbureters act also as atomizers. 

Recent tests have demonstrated that any gasoline or kerosene 
motor can operate with alcohol without any structural changes, and ] 
that about 1.8 times as much alcohol as gasoline is required to 
develop the same power. Alcohol can be used with greater com¬ 
pression, as there is little danger of pre-ignition through too much 
compression on account of its comparatively high ignition tempera¬ 
ture and also because it is always mixed with some water. An 
alcohol motor can be made to give somewhat higher power than a 
gasoline motor of the same size. It is not as sensitive to poor adjust¬ 
ment of the explosive mixture; that is, it will work with a great 
range of strength of mixture, and it does not accumulate a deposit 
of carbon inside the motor. An explosion motor of good design 
should use about 1.15 pounds of alcohol per brake-horse-power hour; 
of gasoline, 0.7 pound. 

Despite all these advantages, denatured alcohol as a fuel has 
not come into wide use, partly because of its high price as compared 
with gasoline and kerosene, partly on account of poor distributing 
facilities, and partly for other reasons. It has, however, attained a 
considerable use among motor car owners as an anti-freezing solu¬ 
tion and as a decarbonizer. For the former, a small quantity is 


EXPLOSION MOTORS 


75 


added to the water in the radiator in the winter months, reducing 
the temperature at which this will freeze, according to the quantity 
added. It is possible to add enough to give a solution which will 
not freeze until 32 degrees below zero is reached. As a decarbon¬ 
izer or remover of carbon formations in the cylinder, denatured 
alcohol is excellent, while its use is the essence of simplicity. It is 
to be hoped that the production will be materially increased in the 
next few years so as to reduce the price, increase its availability, 
and thus make it possible to help out the fast-failing gasoline 
supply. 

Other Automobile Fuels. Benzol. In England, a fuel called 
“benzol” is used to a considerable extent. This is a by-product of 
the destructive distillation of coal, that is, it is produced in the 
manufacture of coal gas. In large plants a considerable quantity 
can be made, for the yield is something like three gallons per ton of 
| coal burned. It is naturally a foul-smelling, dark-brown liquid, 

; but by a refining process is made a transparent white, like water, 
and the odor partly removed. It has a specific gravity of .88 at 60 
degrees F., a flash point of 32 degrees F., and a heating value of 
about 17,250 B. T. U’s per pound. Although not as volatile as 
gasoline, it starts readily and, when carefully refined, does not leave 
| a residue, or carbonize in the motor. 

Electrine. In France, a mixed fuel composed of half benzol and 
half denatured alcohol is much used, this bearing a number of trade 
! names. One of these called “Electrine,” has a specific gravity at 
15 degrees C. of .835. 

Naphthalene. Mention has been made previously of a solid 
fuel, naphthalene. This is a white solid substance, produced during 
| the manufacture of gas from coal, and previously was a waste prod¬ 
uct. It now sells at about 3 cents a pound. In a less pure state it 
is well known to all in the form of camphor balls, so-called. To use 
this as a fuel in an automobile engine, it must be melted to a liquid, 
then turned into a gas and mixed with the right proportion of air. 
None of these offer any particular difficulty, and it has been used 
abroad with marked success, particularly on a long test by a 40- 
horse-power motor truck. After the trip, the cost, using naphthalene, 
figured out to 0.6 of a cent per horse-power hour, while a similar 
truck, running side by side with this one, on gasoline cost 2.6 cents 


85 




76 


EXPLOSION MOTORS 


per horse-power hour. In its first trial then, this fuel showed four 
times the economy of gasoline. 

Solid Gasoline . A number of attempts have been made to 
produce gasoline in a solidified form so that it could be handled 
more easily and much more safely. In Europe, this has been accom¬ 
plished satisfactorily, the resulting substance being of about the 
consistence of jelly. In general its properties are about the same as 
liquid gasoline, except that it occupies less space, a gallon when 
solidified taking up about 185 cubic inches as compared with 231 
before. The principal argument against its use is the size of the 
vaporizing device needed to change it to a gas and add air. 

FUEL MIXTURE 

Explosibility. If a combustible vapor be mixed with air in 
certain proportions, the result is an explosive mixture. Every mix¬ 
ture will possess certain qualities, depending upon the ratios of air 
to vapor in each case, and under the same conditions certain pres- j 
sures and temperatures will result from the combustion of each ; 
mixture. The highest pressures and temperatures result from the 
explosion of those mixtures which contain just sufficient oxygen to 
support the combustion of the explosive vapor contained in the 
charge. According to Clerk, the highest velocity of flame propaga¬ 
tion occurs when the vapor is a trifle in excess of that contained in 
the ideal mixture. 

Any variation in the composition of the mixture either way 
from the theoretical ratio results in decreasing the maximum pres- 1 
sures and temperatures of combustion and in making the explosion 
occur more and more slowly until finally we have a slow combustion, 
i-e ., the mixture ceases to be explosive. It has been found that 
approximately 15 pounds of air are required per pound of gasoline 
for the true explosion mixture. 

In actual practice, to make sure that complete combustion 
results, an excess of air is usually employed, the latter being beneficial 1 
also in that the maximum temperatures are reduced, which reduce 
the per cent of heat lost to the cooling water. This excess also 
reduces the danger of pre-ignition. The theoretical ratio of the 
number of volumes of air per unit volume of gasoline vapor for 
the true explosive mixture is between 25 and 30, while the explosive 


86 



EXPLOSION MOTORS 


77, 


range of the mixture extends below these values to about 19.5 
and above them to a value of about 40.5. 


HORSE=POWER AND RATING CALCULATIONS 


The unit of mechanical power, the horse-power, is equivalent to 
the performance of 33,000 foot-pounds of work per minute. In a 
four-cycle motor, as an explosion occurs every two revolutions, 
there are twice as many revolutions as explosions or cycles per 
minute. To calculate the horse-power of such a motor, therefore, the 
number of foot-pounds of work done at each explosion (call it W) 
must be multiplied by the number of explosions or by one-half the 


number of revolutions per minute (^> 


and this product 


divided by 33,000. The result will be the horse-power (h. p.) of 
the motor. Expressing this in equation form it becomes 


W Xr.p.m. 
2X33,000 


Indicated Horse=Power. In actual practice the indicated horse¬ 
power of an automobile engine means little or nothing. What is 
needed is a simple, easily understood formula by means of which 
anyone can figure out a rating horse-power. This is used for pur¬ 
poses of comparison, for a basis of automobile taxation, for legal 
purposes, handicapping races, and otherwise. 'In gasoline engines 
for stationary power purposes, and, at times, in automobile motors, 
the indicated horse-power is desired for figuring. When this is the 
case, it is figured from the indicator card by means of the following 
formula: 

PLANK 
'' ' P ' 33,000 


in which P is mean effective pressure (m. e. p.) in pounds per square 
inch; L, length of stroke in feet; A, piston area in square inches; 
N, number of cycles per minute or one-half the number of revolu¬ 
tions per minute; and K, number of cylinders. 

The mean effective pressure P is obtained from the indicator 
card by going around it with a planimeter* in the way in which it 

*A nlanimeter is an instrument which indicates the area of an irregular figure by tracing 
the boundary of the figure. The area of the indicator card may be approximated by dividing 
it into a series of rectangles and taking the sum of the areas. 








78 


EXPLOSION MOTORS 


was traced, that is, in order 1-2-3-4-5-1 , Fig. 73. The indicator 
card consists really of two areas or loops, of which 3-4-5 represents 
positive work, and 1-2 negative work. The total work done on the 
piston is represented by the difference between these two areas. The 
small area 1-2 represents the work done in overcoming the friction 
resistance of the gas when being admitted to and expelled from the 
cylinder. It is work that has to be done by the motor; is a definite 
loss of power; and should be made as small as possible. The area 
3-4-5 is the work that is actually done on the piston, less the work 
required to compress the gas; it is the true work of the cycle, all of 
which would be available for driving the engine, were it not for the 
gas-friction resistances represented by the area 1-2. See also the 
negative loop, Fig. 72. If a planimeter is made to trace the diagram 
in the order in which it was drawn, it will go around the area 1-2 
and 3-4-5 in opposite directions; that is, if it goes around one clock¬ 
wise, it will go around the other counter-clockwise. The consequejice 
is that the readings of the planimeter will give the desired difference 
in square inches between the two areas 3-4-5 and 1-2. The mean 
effective pressure is then obtained in the usual manner by dividing 
this area by the length of the diagram and multiplying by the “scale” ] 
or constant of the indicator spring. 

Mechanical Efficiency. The figures just given refer to the 
indicated horse-power (i. h. p.), which is the work done upon the 
piston by the charge. The object of the motor, however, is to drive 
some other machine or apparatus. 


It is, therefore, important to rec¬ 
ognize the distinction between 
the indicated work done in the 
cylinder and that quantity of 
work, always smaller, which the 
motor does against external re¬ 
sistance. This work against ex¬ 
ternal resistance is termed the 



Fig. 73. Indicator Card from Otto 
Cycle Motor 


brake horse-power (b. h. p.), or delivered horse-power (d. h. p.). The 
term brake horse-power is usually applied to the power absorbed 
by a friction brake attached to the rim of the flywheel or to the shaft. 

Prony Brake. The most commonly applied form of friction 
brake is that one known as a prony brake, one form of which is shown 







EXPLOSION MOTORS 


79 


in Fig. 74. This device consists of a series of wood blocks D con¬ 
nected by a leather or iron strap and arranged so as to rub on the 
surface of the flywheel of the engine to be tested. The two arms of 
the brake rest on a pair of scales. The hand wheel, shown at E, is for 
varying the amount of friction. The horizontal distance R from the 
center of the wheel to the end of the arms is known as the brake arm. 

In using the brake, the load is applied by turning the screw E 
and is measured by the reading on the scale. Before the load is 
applied, and the brake arms are resting on the scale, as shown in the 
figure, the scale must be read to determine the amount required to 
balance the overhanging brake arms. This amount must be deducted 
from the reading of the scales when the load is applied, in order to 



Fig. 74. Prony Brake for Testing Motor Efficiency 


give the net load. This may be done in either one of two ways: 
The scales can be turned back and readjusted so as to record nothing 
when the brake arm is resting on the scales; or, without correcting 
the scales, the deduction can be made when the final power is figured 
out, that is, the weight which the brake arm alone depresses on the 
scale beam must be subtracted from the total scale reading to give 
the net load on the scale. 


The b.h.p. is calculated by the formula 


b.h.p. 


2TanW 

33,000 


in which n is revolutions per minute; a, length of brake arm in feet; 
W, the net load on the scales; and t, 3.1416. 

The brake horse-power is less than the indicated horse-power 











80 


EXPLOSION MOTORS 


by an amount which represents the loss due to friction of one kind 
and another in the mechanism of the motor itself. 

The ratio of the b. h. p. to the i. h. p. is the mechanical efficiency of 
the motor, that is, 


mechanical efficiency =7 


b.h.p. 


i.p.h. 


Good motors have a mechanical efficiency of from 80 to 95 per cent, 
referring to modern automobile motors. Other motors, as stationary 
gasoline or gas engines, have a lower figure, say from 70 to 80 or, 
possibly, 82. 

Estimating Motor Horse=Power. An inspection of the i.h.p. 
formula above given will show that if we are able to presuppose 
some certain mean effective pressure (m.e.p.), we have the most 
practical way of estimating the horse-power of any explosion motor 
whose length of stroke, piston area, and revolutions per minute are 
known. 

The mean effective pressure secured in gasoline engine prac¬ 
tice ranges from a minimum of 45 or 50 pounds to the square inch, to 
a maximum of about 125 pounds to the square inch. For the above 
purpose, 60 pounds may be assumed as very close to the m. e. p. 
of most automobile motors, though in sleeve valve and other types 
in which the combustion chamber is approximately spherical, the 
mean effective pressure will often be as high as 85 pounds. In any 
case, for a given type of motor there is never any considerable varia¬ 
tion from a certain mean effective pressure that is characteristic of 
its type. This pressure being known, it becomes a matter of simple 
arithmetic to calculate the power from a given stroke, cylinder 
diameter, or piston area, at a given number of revolutions per 
minute, i.e., by a direct substitution in the formula for i.h.p. 
given on page 77. 

For two-cycle motors the compression is usually lower than in 
the four-cycle type, and it is safe to assume that the m.e.p. is not 
over 70 to 75 pounds. In applying the formula for the i.h.p. to the 
two-cycle motor, N becomes the number of revolutions per minute, 
since there is an explosion in each revolution. 

Electric Dynamometer. The electric absorption type of 
dynamometer is a testing device, operating on the same principle 
as the Prony brake. It is, however, more accurate, more complete, 





EXPLOSION MOTORS 


81 


easier to use and, in other ways, has a distinct advantage over the 
older form of hand-applied brake, which is now nearly obsolete, as 
well as over other forms of absorption brake, such as the coil of rope 
form, the water brake, the centrifugal pump, the air fan, and others. 
The electric type is practically a measuring dynamo, which is driven 
by the engine being tested and, when so driven a magnetic action 
is set up between its field pieces and armature, which can be meas¬ 
ured precisely in electrical units. When this is done, the quantity, 
in foot-pounds of energy exerted through a given radius, is an exact 
measure of the torque or turning power of the engine. 

The radius, like that of the brake arm of the hand-operated 
form, may be of any desired length, but if 15f * inches is used, this 
simplifies the usual Prony brake formula to 

k k _ weight in pounds X r.p.m. 

' P '~ 4,000 

in which the weight is measured by means of a pair of scales, usually 
of the double-beam type, with a fine reading to pounds and tenths 
on one beam and a rougher reading for quick but approximate 
determinations on the other. The revolutions will be indicated by 
means of an electric speedometer, supplemented usually by a form 
of tachometer to be used as a check. With but two variable quan¬ 
tities, the weight and speed, it is possible to lay down the curves 
for every possible combination of speed and weight, so that the 
power can be read at a glance by simply following out the two lines 
to their point of intersection. 

With this form of device, it is possible to have the electric load¬ 
ing arranged in such a manner that it resembles the well-known 
rheostat used on trolley cars, and like it is turned on by means of a 
rotating handle or wheel. In that case, the tester simply sits at a 
table making his readings and gradually turning the wheel to 
increase or decrease the load. 

Auxiliary Apparatus. When using electrical testing apparatus 
of this kind, it is possible to have many additional auxiliary features 
of value. For instance, by turning on the electric current, the 
dynamo acts as a starting motor to turn the engine over, until it 
starts. In case the test is to be a long-drawn one, the electrical 
energy generated need not be wasted as with other forms of brakes. 



82 


EXPLOSION MOTORS 


but can be wired to electric motors elsewhere in the plant and 
utilized, this disposition of it having no influence whatever upon 
the measurement of the energy. In addition, automatic or self- 
registering instruments may be had, so that an operator is not 
needed, after the test has been started, except to stop it. Further, 
an automatic gasoline-measuring scale may be had, which is elec¬ 
trically operated, this being constructed to register the number of 
revolutions and the elapsed time for each pound of fuel consumed. 



Fig. 75. Electric Dynamometer for Testing High-Speed Automobile Engines 
Courtesy of Sprague Electric Works, New York City 

Fig. 75 shows the complete dynamometer with scales and 
measuring devices, as made by the Sprague Company, while Fig. 76 
shows the complete layout of a similar outfit as made by the Diehl 
Manufacturing Company, this indicating the actual test of a six- 
cylinder motor. 

Importance of Testing to Repair Man. It is particularly impor¬ 
tant that the repair man be well equipped in the matter of testing 
apparatus. In fact, every well-equipped garage should have some 
form of horsepower testing outfit, either one of those just described 







EXPLOSION MOTORS 


83 


or else some similar homemade affair. What is needed by the 
repair man, however, is not so much a measuring apparatus as a 
loading device, whereby loads may be thrown upon engines which 
have hidden troubles, or which have just been repaired, so as to 
allow the motor to act as it would when actually pulling the car 
with a standard load. 

An advantage of a loading device of this kind is that troubles 
which are otherwise hard to find can be discovered in a short time 
inside the shop instead of after long, extended, and expensive outside 
runs to determine the exact part which is at fault. With a loading 
device, a stethoscope (such as is described elsewhere in this work), 
and a full set of electrical testing instruments, a garage or repair 
man, who is onto his job, can in a short time locate the trouble with 
any engine, transmission, or any other part of a complete car with 
the trouble located, the difficulty is half overcome. 

The repair man can buy at a reasonable figure testing outfits 
which are designed solely for the purpose of finding out electrical 
sources of troubles (and many others) in the shortest possible time. 
These are called trouble-finding or trouble-shooting outfits, and a 
number of them are now marketed. 

Lacking a stethoscope to use with a testing or loading outfit, 
many garage men make use of a substitute in the form of a plain 
steel rod of small diameter. By holding one end of this rod between 
the teeth with the other end placed on or near the suspected engine 
part, one can train the ear to recognize, by means of the vibrations 
which come to it through the rod and teeth, whether or not the part 
is running exactly right. In many cases, such a testing or loading 
outfit is a good preventive of trouble, enabling the owner to locate 
the trouble and correct it before it can get serious enough to cause 
excessive difficulty or expense. The adage “A stitch in time saves 
nine” applies equally well to an automobile and many owners 
would have much less trouble if they or their chauffers understood 
this better. 

Rating. At one time practically all automobile engines were 
given a hyphenated rating, as for instance, 30-60 horsepower. This 
represented the power developed at a normal speed and the maximum 
output of which it was capable. In general, the difference was not 
as great as in the example given, although this represents an actual 


84 


EXPLOSION MOTORS 


rating of a well-known American car motor. As has been stated, 
rating allows of a comparison when the same basis is used by every¬ 
one; that is all it is for. Now, ratings are worked out from various 
formulas. The one used throughout the United States is that known 
as the S.A.E. formula, after the Society of Automobile Engineers, 
sponsors for it. This was formerly called the A.L.A.M. formula 
because the now-defunct Association of Licensed Automobile Man¬ 
ufacturers placed their seal of approval upon it, and brought it into 



Fig. 76. Electric Dynamometer Coupled up to Six-Cylinder Engine for Test 
Courtesy of Diehl Manufacturing Company, Elizabeth, New Jersey 


general use in this country. It originated in England, where it is 
still in universal use as the R.A.C. formula. It is as follows: 


h.p.= 


D 2 N 

2.5 


in which D is the diameter of the cylinder bore in inches and N is 
the number of cylinders. As N is usually 4, 6, or 8, it is possible to 
simplify the formula to: 

h.p. = 1.6 D 2 (for four cylinders) 
h.p. = 2 AD 2 (for six cylinders) 
h.p. = 3.2 D 2 (for eight cylinders) 

While no account of the stroke appears to have been taken in figuring 




















EXPLOSION MOTORS 


85 


this out, yet in the original determination of the value of the con¬ 
stant 2.5 used, 1,000 feet per minute was considered as a fair 
average piston speed. As the length of the stroke determines the 
piston speed, it is apparent that consideration was given to the 
length of the stroke, and that this factor is in the formula. How¬ 
ever, for the benefit of those desiring the length of the stroke incor¬ 
porated, the following formulas have been developed and are in use: 

Roberts’ formula, 

, D 2 LNR 


Dendy-Marshall formula, 


h.R = 


D 2 SN 

12 


substituting the number of cylinders, this becomes 


h.p. = .33 D 2 S (for four cylinders) 
h.p. = .5 D 2 S (for six cylinders) 
h.p.= .66Z) 2 *S (for eight cylinders) 

! White and Poppe formula, 


h.p.= 


DSN 

16 


in which, however, the diameter D and the stroke S are in centi¬ 
meters. Substituting the number of cylinders as before, this becomes 

h.p.= .25 DS (for four cylinders) 
h.p. = . 38 DS (for six cylinders) 
h.p. = .5 DS (for eight cylinders) 

Racing Boat Formulas. The following formulas are for high¬ 
speed racing boat engines of four-cycle type, and are based on 1,000 
feet per minute piston speed. For engines of ordinary design, two 
thirds of the above values should be taken; 10 per cent should be 
added to the ratings if the charge is forced into the cylinders by any 
mechanical device. 

American Power Boat Association, 


, D 2 N 
P ' 2.5338 


95 









86 


EXPLOSION MOTORS 


For motors of less than 6-inch stroke, 



D 2 LN 

15.20 


Two-Cycle Formula. The following are two-cycle engine for¬ 
mulas, the first being by Roberts for racing-boat engines and the next 
two by the American Power Boat Association: 


h. p.= 


B 2 LRN 

13,500 


D 2 N 

2.1008 


, D 2 LN 

h. p. —-- 

12.987 

The above formulas by the American Power Boat Association 
are only for racing-boat engines. For ordinary two-cycle-boat 
engines two thirds of the value resulting from the use of these for¬ 
mulas should be taken. For engines having one or more displacer 
cylinders, the above rating should be increased in the ratio that the 
displacer pistons’ displacement bears to that of the working cylinders. 

Comparison of Power of Two- and Four-Cycle Motors. It will be 
noticed that in a two-cycle engine having double the number of power 
strokes of a four-cycle, the h.p, would be multiplied by 2. This, 
however, would give an erroneous result, as there are many inherent 
conditions connected with two-cycle engine design which tend to 
lower its horse-power output, such as the lower compression, lower 
m.e. p., due to inefficient scavenging, etc. For these reasons the 
output varies more in two-cycle engines than in four-cycle engines, 
and is very often taken as approximately 1.35 of that of a four¬ 
cycle engine of the same bore and stroke. There are, of course, 
exceptional cases where two-cycle engines have shown considerably 
better than this value, but it is considered an average result. 


96 




































































































































































































... 


































' 












































. 






































































- 










































AUTOMOBILE TRUCK STRIPPED FOR REPAIR WITH GAS-WELDING OUTFIT 

Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 



WELDING BROKEN FRAME OF AUTOMOBILE TRUCK 

Courtesy of Oxw eld-Acetylene Company, Chicago, Illinois 


























WELDING IN AUTOMOBILE 
REPAIR SHOPS 


INTRODUCTION 

Development of the Field. The rapid growth of the automobile 
industry is merely the result of a steadily increasing demand for 
improved transportation facilities, and this demand covers vehicles 
for industrial uses as well as for pleasure purposes. Since the 
automobile or motor car is now such an important part of our 
modern equipment, it has become necessary to provide increasing 
facilities for its care and maintenance. 

This has resulted in the establishment of garages for the storage, 
and repair shops for the maintenance, of the motor truck and the 
motor carriage. Many industrial establishments have large fleets 
of motor trucks and maintain complete repair shops of their own, 
but the majority of car owners are dependent upon public shops 
for the care and maintenance of their machines. 

General Repair Equipment. The equipment required for a 
modern repair shop should be complete enough to enable the 
mechanics to do almost any sort of job around an automobile of 
any type, but it seldom is necessary to invest large sums of money 
in elaborate shops or equipments, or to prepare for repair jobs of 
rare occurrence. The total requirements of repair shops would be 
beyond the scope of this article, but it is safe to say that all shops 
catering to the public, and all private ones maintaining large num¬ 
bers of cars, should have some kind of welding apparatus available 
for immediate use. 

Need for Welding Outfit. Originally the term welding was 
limited to the kind of work done by blacksmiths when joining two 
pieces of iron or steel by heating and hammering. Other and better 
systems of joining metals are now possible because of the develop¬ 
ment of improved methods of obtaining high temperatures through 
the use of gases and electricity. These newer methods of joining 
metals are also called welding and can be used in joining many of 


99 



2 


AUTOMOBILE WELDING 


the metals which cannot be welded by hammering. As a matter 
of fact, any process which causes cohesion between the molecules 
of the two pieces to be joined may rightfully be called welding. 
This excludes such processes as soldering or brazing, because in 
the latter cases a kind of metal different from the pieces joined is 
used to hold them together. Welding involves the use of metals 
of the same kind for the joint. 

Conditions Favorable to Successful Welding. Plasticity. Met¬ 
als are most easily welded when in a condition of plasticity just 
between the molten and the solid states; hence, those metals which 
remain plastic the longest after fusing are the easiest to weld. Iron, 
platinum, nickel, and gold have been hammer-welded for many 
years, but recent inventions have greatly extended the field, and 
now nearly all metals may be welded by some process. Even 
aluminum castings may be welded by both the gas and the electric 
arc processes and most of the alloys may also be welded successfully. 

Flow , Cohesion , and Temperature. Successful welding by any 
process depends almost entirely upon three factors—flow, cohesion, 
and temperature. The metal must tend to flow when under pres¬ 
sure, even if to but a slight degree. The surfaces of the pieces 
to be welded must tend to “wet” each other and stick together, 
or cohere, to an appreciable extent when heated. The working 
temperature must be that at which the foregoing conditions are 
most prominent. The best welding condition for any metal exists 
within a limited range of temperature only, hence it is very important 
that the operator should know how each kind of metal acts when 
fused and welded by the various processes now in use. This can 
be learned only by study and experience, but it is fully worth while 
because the demand for good welding operators is increasing faster 
than the supply. 

WELDING PROCESSES 

Classification of Methods. There are several processes of 
joining metals, but there are only four kinds of welding processes 
in use—smith or forge welding, sometimes called blacksmith welding; 
electric welding, including contact and arc welding; gas or hot- 
flame welding; and chemical welding. For automobile repairs, 
electric arc and gas welding are used almost entirely because of 






100 


AUTOMOBILE WELDING 


3 


their convenience, simplicity, and economy. In order that the 
student may be informed regarding all of them, we will describe 
them here in a general way, and then give some detailed applications 
of the two most used in automobile repair shops. 

Smith Welding. Smith welding, or forging, is the general 
process of forming or joining metals by hammering or pressing the 
pieces into the desired shape, and may be done either hot or cold, 
depending upon circumstances. When joining two pieces of metal, 
especially iron or steel, it is done hot and is one of the oldest of 
the useful arts. It is the most common of all welding processes, 
but depends more upon the skill of the operator than any other 
process of welding; on this account, and because it is also rather 
expensive and slow, it is gradually being superseded. 

Electric Welding. Electric welding was used as a laboratory 
experiment for a number of years, but recently the process has been 
developed to such an extent that it is rapidly coming to the front 
as the most important of all welding processes. Two distinct 
methods have been perfected, the one used for automobile repairs 
being based upon utilizing the heat of the electric arc to fuse 
metals into place. The other process provides for the passage of 
a heavy current through the joint between the pieces, allowing the 
resistance of the bad contact to heat the pieces until they are soft 
enough to stick together; squeezing the pieces while soft will then 
cause them to stick. This process is used mostly in making auto¬ 
mobile parts—such as mud guards, bonnets, etc.—rather than for 
repairs. The electric arc-welding process will be described in 
detail later. 

Gas Welding. Gas welding, or hot-flame welding, is at present 
used to a greater extent in automobile repair shops than any other 
system of welding, because the first cost of the equipments is com¬ 
paratively small and also because acetylene headlights were formerly 
used on automobiles and gas was very easily obtained. The system 
is very good for most operations, and there are now three important 
processes in commercial use, known as the oxy-acetylene, oxy-hydrogen, 
and blau gas processes. The oxy-acetylene and oxy-hydrogen 
processes are the ones used in America almost exclusively and will 
be described in detail later. They all consist in using oxygen and 
another gas to give a flame of sufficiently high temperature and 


101 


4 


AUTOMOBILE WELDING 


heating capacity to melt the material to be welded, the gas used 
with the oxygen being indicated by the name of the process. In 
all cases the oxygen and the other gas under pressure are mixed 
in the burner chamber in suitable proportions, and when ignited form 
a very hot flame. This is directed on the work in such a way as to 
cause the metals to fuse and flow together. When no extra material 
is added to form the weld, it is said to be autogenous or self-forming, 
and this expression also applies to electric arc welding when done 
with the graphite electrode. 

Chemical Welding. Chemical welding is exemplified today 
almost exclusively by the process known as “Thermit Welding”, 
and consists of igniting a mixture of oxide of iron and aluminum so 
as to set up a chemical reaction which evolves an intense heat. 
A suitable mold must be constructed about the joint to be welded, 
and the operation carried out in such a way as to form a heavy 
reinforcement at the joint. This really forms a cast-weld and is 
very effective in places where it can be used, but the process is 
usually limited to jobs of comparatively large size because of the 
cost. For this reason it is not used for automobile repairs to such 
an extent as the other processes mentioned. 

METHODS OF PRE=HEATING 

Necessity of Pre=Heating. For a great many welding opera¬ 
tions it is necessary to heat the parts to a bright red heat before 
starting the welding, especially in the case of cast-iron engine cylin¬ 
ders, etc., when machining is to be done on the pieces at the weld. 
Unless the parts are carefully pre-heated they will be too hard to 
machine, and are liable to crack when cooling. For smith welding 
it is necessary to heat most metals to the point where they almost 
begin to flow before they can be welded. This is especially true 
of iron and steel, both of which are used extensively in automobile 
construction. 

Production of Temperature. The combustion of fuel—either 
coal, coke, oil, or charcoal—causes the oxygen of the air to combine 
with the carbon of the fuel, and this chemical combination is what 
produces heat. The amount of heat depends upon the amount 
of carbon and oxygen combined during combustion, whereas the 
temperature attained depends entirely upon the rapidity with which 


102 


AUTOMOBILE WELDING 


5 



the combination takes place. This is one of the most important 
facts to be learned in connection with welding, because the principle 
involved applies to all systems of welding. 

Torches and Forges . Torches are most commonly used for 
heating when the work cannot be easily moved; they are designed 
to use gas, oil, or gasoline, either with or without compressed air 
to assist in combustion. Forges are the most economical means 
of producing heat when they can be used, burning coal, coke, or 
charcoal — the latter giving the best results because it is free from 


Fig. 1. Modern Motor-Driven Forge 
Courtesy of Canedy-Otto Company 

impurities. The coal and coke used must be free from sulphur 
and phosphorus, for sulphur makes iron hot-short , or brittle, when hot, 
and phosphorus makes it cold-short, or brittle, when cold. Both 
of these elements will be absorbed by the metal when hot. Copper, 
lead, tin, and other non-ferrous metals should be kept out of the 
fire as they will spoil iron or steel for welding. 

Forced Draft. Under ordinary conditions, combustion alone 
would not be rapid enough to generate the amount of heat or tem¬ 
perature required for welding, so a forced draft is created through 
the fire or flame in order to supply sufficient oxygen to the fuel and 




6 


AUTOMOBILE WELDING 


increase the rate of combustion. Too much air will chill the fire, 
or perhaps blow it out, and an excess of oxygen will cause some of 
it to combine with the iron and form a scale of oxide of iron. This 
latter is called an oxidizing fire; whereas, if the oxygen is all con¬ 
sumed in the fire and there is an excess of carbon, it is then called 
a reducing fire. When welding with oxy-acetylene or oxy-hydrogen 
flames, it is also important that the proportions between the gases 
be properly maintained to prevent the formation of oxidizing or 
reducing flames. 

Where the draft is provided by means of a forge, Fig. 1, the 
work may be laid on the fire and fuel piled up around it, if the 
article is small. If it is a large piece, it will usually be necessary | 



Fig. 2. Temporary Brick Furnace for Pre-Heating Work 


to construct a temporary furnace with a few fire bricks, Fig. 2, 
and to build a good charcoal fire therein; but care should be taken 
to prevent overheating the piece. If torches are to be used, it 
will usually be best to also build a temporary furnace in which the 
piece can be placed, with arrangements to allow a torch to be placed 
each side of the furnace with the flames directed into it and on the 
piece. 

Facilities for Handling Pieces and Keeping Them Hot. Some 
suitable means should also be provided for handling the hot articles 
so that they can be placed on the work table for welding; or a por¬ 
tion of the furnace should be quickly removable to give access 
to the piece as it lies in place. Work should be done while the piece 
is as hot as possible, and the furnace again closed to allow the piece 

























































AUTOMOBILE WELDING 


7 


to cool slowly. If the piece is welded outside of the furnace, some 
suitable non-heat-conducting material, such as ashes or flake asbes¬ 
tos, should be piled around the article to keep in the heat and cause 
slow cooling. Welds made on iron castings treated in this manner 
should be as soft as the original casting. 

When heating articles to be welded, care should be taken to 
consider the shape of the piece and to heat it in such a way that it 
will not expand unequally and cause cracking at some other place. 
If this is done right, it will not be necessary to heat the entire piece, 
thus saving a great amount of time in many instances. This 
is especially true when the article is of closed shape, such as a spoked 
wheel or gear. 


ELECTRIC ARC WELDING 

The Electric Arc. The use of the electric arc as a source of 
heat is one of the oldest applications of electricity, both for cutting 
metals and for fusing them together, but until a comparatively 
| few years ago it was done on only a small scale. The electric arc 
\ has been given a great amount of study, and yet very little is known 
| about its most important characteristics. The exact temperature of 
the arc is not known, but this is estimated at about 4000 degrees 
1 centigrade (7200 Fahrenheit, approximately), because it will melt 
all known substances. This makes it a very efficient source of 
heat and indicates why electric arc welding is the process that 
is so rapidly coming to the front for all purposes. 

About seventy-five years ago it was discovered that the electric 
current w T ill flow more easily from metal to carbon than in the 
reverse direction; it was also found that the current through an 
arc is greater when passing from an easily oxidized metal to one 
that is less so, than when flowing in the opposite direction. This 
is easily understood, because the conductivity of an arc depends 
largely upon the kind of vapor in the arc, and to some extent upon 
the ease with which the welding electrode can be kept at a high 
temperature. In the arc-welding systems in use today, the arc 
is drawn between metal and carbon or between metal and metal. 
Since the positive electrode, or terminal, of an arc reaches a higher 
temperature than the negative electrode, or terminal, it is more 
efficient to use the article worked upon as the positive electrode 


8 


AUTOMOBILE WELDING 


of the arc. This is done by attaching to the job the line, or wire, 
from the positive side of the machine. 

Since iron or steel are more easily vaporized than carbon, the 
current flows more easily from iron to carbon than the reverse 
because there is more iron vapor than carbon vapor in the arc. 
This is also proved by the fact that it requires more voltage to send 
a given current through an arc between carbons than between 
metal electrodes. It is also important that the negative electrode 
be kept at a high temperature, and the usual practice of having 
the negative electrode small (due to the use of a wire or of a carbon 
pencil) makes this easily possible. 

Arc=Welding Process. The process of welding or cutting 
with the electric arc is possible with nothing more than a source 
of current at a suitable voltage, some means for regulating the 
amount of current flowing, and an electrode. However, the work 
done with such a crude system will not be satisfactory nor commer¬ 
cially acceptable, so certain other devices are necessary to insure 
a first-class job. In order to do welding or cutting with the electric 
arc, after suitable equipment has been provided, it is necessary 
to first connect the work to the positive side of the power supply 
circuit and the welding electrode to the negative side of the circuit, 
by means of wires or cables, with the regulating devices in circuit 
to control the amount of current flowing. The negative electrode 
should then be placed lightly in contact with the work, Fig. 3, and 
quickly withdrawn to make the circuit and draw the arc, thus provid¬ 
ing the high temperature required for welding. The metal will begin 
to melt immediately and work may then proceed until finished. 

Electric arc welding usually consists in using the heat of the arc 
to fuse or melt the filling material into the place to be filled, although 
the article worked upon may be melted down sufficiently to fill 
the space if it is large enough at the point to be welded. Two 
methods or processes of using the arc for welding are in commercial use 
today, these being the metallic and the graphite , or carbon, processes. 
The metallic welding process consists in using a piece of wire 
of the proper kind as the negative electrode of the arc and fusing 
it into place drop by drop; the graphite process consists in using 
a piece of graphite, or carbon, as the negative electrode and fusing 
a piece of metal into place by the heat of the arc, similar to a gas 


AUTOMOBILE WELDING 


9 


process. The graphite process is always used for cutting, a slot 
being melted through the piece to be separated; this is a very 
economical method for this purpose. Further reference to these 
processes will be made when describing their applications. 

Arc=Weldingl Equipment. General Features . The equipment 
required for electric arc welding in automobile repair shops will 
depend largely upon the kind and amount of work to be done, 



Fig. 3. Operator Using Metallic Electrode 
Courtesy of C & C Electric and Manufacturing Company 
Garwood, New Jersey 


but the most complete equipment allows of the best work the same 
as with any other sort of apparatus. The use of resistances only, 
as the means of regulating the amount of current flowing, is very 
wasteful, so other apparatus must be used for the sake of economy. 
It is well known among electrical men that a motor-generator set 
gives the best regulation of voltage, therefore, the leading welding 
outfits in use today consist of motor-generator sets with suitable 
control apparatus for motor, generator, and welding circuits. Fig. 4 
shows a typical wiring diagram for an arc-welding outfit, and it 
will be seen that the switchboard contains all of the instruments 


107 




10 


AUTOMOBILE WELDING 


required for controlling the machine, and also the resistance switch 
for regulating the amount of current flowing through the arc. The 
connections are very simple and the operation and care of the 
apparatus .are easily learned by any good mechanic. 

There are several companies manufacturing electric arc-welding 
outfits suitable for automobile repairs, each company offering its 
apparatus on the strength of some peculiarity of the machines 
or devices for their control. In all cases the equipment furnished 
consists of the welding machine proper and its control panel, face 
shields for the operators to protect their eyes from the bright arc, 



Fig. 4. Standard Layout and Connections for Low-Voltage Motor- 
Generator Welding Outfit 


and suitable electrode holders with cables. Full instructions for 
the installing and use of the apparatus are also given, and in some 
cases expert demonstrators are sent out to instruct the users in 
the best methods of performing various operations. For welding 
broken engine cylinder castings it will require an outfit of 300 to 400 
amperes capacity, and the same size is required for cutting, Fig. 5. 
A machine of this capacity will be large enough for two men on 
steel work, and outfits up to 1200 1 amperes capacity can be obtained 
where several men are required to work at once. For most automobile 
repair shops, however, a single-circuit machine for one operator 
will be sufficient, having a capacity of 150 to 200 amperes at about 
50 volts, Fig. 6. With such an outfit it is possible to weld main 
frames, cross-members, steel crank cases, broken crankshafts, mud 
guards, steel bodies, bonnets, brake parts, valve stems, cam-shafts, 
driving shafts, broken gear teeth, rear axle housings, steel rims and 
hubs, etc. 

Portable Sets. When conditions require work to be done 


108 






































AUTOMOBILE WELDING 


11 



Fig. 5. 300-Ampere Welding Set with Control Panel and Auxiliary Welding Panels 

Courtesy of C cfc C Electric and Manufacturing Company, Garwood, New Jersey 



109 















Fig. 7. Portable Arc-Welding Outfit 

Courtesy of C & C Electric and Manufacturing Company, Garwood, New Jersey 

motor truck and taken anywhere; its control panel will be similar 
to the one shown in Fig. 7. Machines of these types are made in 
one-, two-, or three-man sizes and can be made to pay handsome 
profits. A machine of either type can also be used in the shop 
when not out on emergency repair work, and can be used for other 
things than automobile work during the dull seasons. 

Current Required for Welding. Welding operations are of 
various kinds and take differing amounts of current, depending 


12 AUTOMOBILE WELDING 


outside of the shop, as in case of accidents or when the motor car 
cannot be brought to the shop to have the work done, portable j 
equipments will be found very useful. A portable outfit is shown 
in Fig. 7, for use when a direct current is available at the place 
where the work is to be done, and consists of the dynamotor, or 
welding machine, on a steel truck with the control panel containing j 
the machine and welding control attachments. Fig. 8 shows a 
gasoline engine-driven welding generator which can be set upon a 


no 











AUTOMOBILE WELDING 


13 





111 


Fig. 8. Electric Arc-Welding Outfit Driven by Gasoline Engine 
Courtesy of C & C Electric and Manufacturing Company y Garwood 9 New Jersey 































14 


AUTOMOBILE WELDING 


upon the nature of the material worked upon, the size and shape 
of the piece, and the sort of operation to be performed. For example: 
thin sheets of steel require less current than thick ones; cutting 
requires more current than welding; and heavy forgings demand 
different treatment from castings, etc. As a general rule it may be 
said that metallic electrode welding takes from 40 to 160 amperes, ; 
although thin sheets may be welded with as little as 15 amperes 
and heavy ones may demand up to 195 amperes. Graphite arc 
welding averages from 300 to 500 amperes, running from 100 amperes 
on small articles up to 700 amperes on heavy work. Gutting with the 
graphite electrode arc requires from 300 amperes on small sections * 
up to 1000 amperes or more on large pieces, the usual limits being 
between 400 and 600 amperes. Articles such as side frames, rear j 
axles, and housings are welded with the metallic electrode and take 
from 130 to 160 amperes, using a ^-inch diameter wire. Cast-iron 
cylinder castings require from 300 to 400 amperes for cutting out 
and preparing, and about the same for welding. They should 
also be carefully pre-heated before welding; further reference will j 
be made to the handling of cylinder castings. When work is properly 
done by the electric arc process, it should be as strong as the original 
piece. 

GAS OR HOT=FLAME WELDING 

Definition of Process. Hot-flame or gas welding consists 
primarily in joining metals by fusing them together at the place 
desired through the use of a high temperature gas flame as the . 
source of heat. Several combinations of gases are now in use for 
this purpose and new types of apparatus are continually appearing 
on the market, based upon the use of some special feature or gas. 
There are two methods of gas welding in general use, the autogenousm 
and the heterogeneous, the names indicating the difference. The 
word autogenous signifies that the weld is made by the fusion, or 
joining, of the parts without the use of additional metal, whereas 
the word heterogeneous—meaning a mixture, signifies that the weld 
is made by fusing-in additional material to complete the weld. 
The term autogenous has unfortunately come to be applied to all 
forms of gas welding, and some confusion has resulted because 
the statement is often made that neither fluxes nor hammering 


112 


AUTOMOBILE WELDING 


15 


are necessary with that process; actually, a flux is at times beneficial 
for some metals, and hammering will help the strength of joint in 
certain other cases. 

Classification of Processes. Oxygen and hydrogen were prob¬ 
ably the first gases used for welding, and most of the systems of 
; gas welding in use today use oxygen in combination with some other 
gas, the processes taking their names from the particular combina¬ 
tion used. The leading welding processes are known as the “Oxy- 
Acetylene”, “Oxy-Hydrogen” (or 
“Oxy-Hydric”), “Oxy-Pintsch 
Gas”, “Blau Gas”, “Water- 
Gas”, and “Coal-Gas”, the use 
of Pintsch gas (same as is used 
in lighting railroad trains) with 
oxygen being the latest develop¬ 
ment. All of these depend upon 
the use of compressed gases, 
usually stored in strong cylinders 
and mixed in the burner or torch 
i as used; these may be used for 
either welding or cutting. 

Types of Outfits. Large re¬ 
pair shops using considerable gas 
have stationary plants for the 
generation of acetylene and buy 
their oxygen, while the plants 
using the oxy-hydrogen and other 
processes usually buy all of their 
gases. These come in cylinders, 
compressed so as to give large 
supplies in small spaces. Small portable outfits are made with the 
two gas cylinders on a truck, as shown in Fig. 9, but the larger 
plants are permanently installed, as shown in Fig. 10. Where large 
quantities of oxygen are required, it is economical to install special 
generators for it. 

Gases Used for Welding. Acetylene. Acetylene (C 2 H 2 ) is a 
colorless gas with a very disagreeable odor—very largely due to 
the impurities present in it—and is obtained almost exclusively 



Fig. 9. Portable Welding or Cutting Oxy- 
* Acetylene Unit 

Courtesy of Davis-Bournonville Company 





16 


AUTOMOBILE WELDING 


from calcium carbide and water. Great care must be used to see 
that pure carbide is used in order to prevent the generation of 
phosphureted-hydrogen along with the acetylene. Calcium carbide 
(CaC 2 ) is a dark gray slag, formed by fusing lime and coke in the 
intense heat of the electric furnace; it possesses a great affinity for 
water. When it is combined with water (H 2 0), in the proportion 
of 2 parts water to 1 part calcium carbide, a chemical reaction takes 



Fig. 10. 100-Pound Oxy-Acetylene Welding Outfit 
Courtesy of Davis-Bournonville Company 


place which heats the mass and forms acetylene gas (C 3 H 2 ) and lime 
(CaOH 2 0) in the form of ashes. In other words, the carbon com¬ 
bines with the hydrogen to form acetylene and the calcium com¬ 
bines with the oxygen to form lime. One pound of carbide will 
yield about 4§ cubic feet of acetylene gas. 

Hydrogen. Hydrogen (H) is one of the elements and is the 
lightest substance known. It is obtained by the decomposition 
of water into its elements, oxygen and hydrogen, both gases being 


114 

















AUTOMOBILE WELDING 


17 


collected and used. Hydrogen is also sometimes prepared by 
passing steam over coke that has been heated to a dull red, but 
electrochemical processes are so much better that they are gradually 
superseding all others. If the temperature is not too high, when 
; using the hot coke process, carbon dioxide and hydrogen will be 
formed (C+2H 2 0 = 2H 2 +C0 2 ), but the carbon dioxide may be 
removed by passing the gas through a vessel of slaked lime. Hydro¬ 
gen is explosive when mixed with air or oxygen, and when oxygen 
and hydrogen are mixed in a suitable burner fot welding or cutting 
they produce a temperature of about 2500° C. Hydrogen is not 
poisonous, but may cause death if inhaled because it will exclude 
oxygen from the lungs. 

Oxygen. Oxygen (O) is the most important of all of the ele¬ 
ments known to man, and is used as one of the gases in nearly all 
welding processes of the hot-flame type. Oxygen is produced 
i commercially (1) from the air by liquefaction and fractional dis¬ 
tillation; (2) from water by electrolytic action; and (3) from potas- 
j sium chlorate by heating. The production of oxygen from air 
by liquefaction is still the greatest source of supply for it today, 

| but recent developments and improvements in electrolytic apparatus 
have added greatly to the source of supply and reduced the cost 
I in many cases where electric power is cheap and plentiful. Oxygen 
! should be free from chlorine to be suitable for welding, although 
the usual mixture of 5 per cent of nitrogen and 2 per cent to 3 per 
1 cent of hydrogen is no disadvantage. Its production is not a very 
I complicated process but the apparatus is quite expensive, and only 
| those plants requiring 1000 cubic feet or more per week can afford 
to make their own oxygen. It is sold in tanks containing 5, 25, 
50, or 100 cubic feet under high pressure, as desired, and the tanks 
may be either bought or rented and only the gas paid for. The 
tanks can be recharged when empty, and each tank is equipped 
with a reducing valve to regulate the pressure when using. A 
pressure gage must also be used, and leakage must be looked out 
for on account of the high pressure (300 pounds per square inch). 

Miscellaneous Gases. The three gases just described are the 
only ones used to any extent in automobile repair shops, so that 
only brief descriptions of the others will be given. Pintsch gas is 
made from crude petroleum or similar oils and will safely stand a 


18 


AUTOMOBILE WELDING 


high degree of compression. It can be obtained in flasks at pressures 
from 180 pounds per square inch up to 1500 pounds per square 
inch but is used at about 25 pounds per square inch, with oxygen, 
for welding. Coal gas, or illuminating gas, is produced by the 
distillation of coal by heating in a closed retort. One ton of coal 
will produce about 10,000 cubic feet of gas, 1400 pounds of coke, 
12 gallons of tar, and 4 pounds of ammonia, the operation lasting 
about 4 hours. Coal gas is used only for welding metals of low 
melting point and has largely been superseded by other gases. 
Blau gas is really liquefied illuminating gas and is produced by the 
distillation of certain mineral oils in hot retorts; it is not poisonous. 
It is sold in cylinders at pressures of about 1500 pounds and is 
coming into increased use in this country. Water gas is a mixture 
of carbon monoxide and hydrogen and is formed by passing steam 
over or through incandescent coke, similar to the production of 
oxygen, thus causing the steam to decompose into oxygen and 
hydrogen. The oxygen combines with the carbon from the coke 
and forms carbon monoxide, with a little carbon dioxide and a few 
easily removed impurities. Thirty-five pounds of coke are used 
for each 1000 cubic feet of gas. Water gas burns at a very high 
temperature, but is dangerous if it escapes because it is odorless. 

Gas=Welding Processes. The oxy-acetylene and the oxy- 
hydrogen processes are used more in automobile repair shops than 
all others combined, so these will be considered in detail. The 
oxy-hydrogen welding process is the oldest of the gas-welding sys¬ 
tems, but the oxy-acetylene process is. better known because there 
are more people making such apparatus and more outfits in use, 
so that process will be considered first. 

Oxy-Acetylene Process. The oxy-acetylene process is based 
upon the use or combustion of oxygen and acetylene at the tip of 
a suitable torch to produce the heat required for fusing metals, 
the temperature being about 3500 degrees centigrade. The opera¬ 
tion of welding with gas is similar to that already described in 
connection with electric arc welding with the graphite electrode, 
as the flame is the source of heat and the filling material must be 
added as melted. The flame is played against the metal until it 
becomes hot enough to fuse, both the job and the filler being melted 
to insure a homogeneous joint. The torch should be given a sort 


AUTOMOBILE WELDING 


19 


of rotary motion around over the surface of the weld, with a slightly 
forward and upward movement, in order to blend the metal and 
reduce the liability to overheat it. 

Adjusting the Flame . The operator must first learn to adjust 
his flame to suit his work, but there is no rule for the exact pro¬ 
portions of oxygen and acetylene so it is not easy to learn. It 
can be learned by practice, however, if there is no instructor available, 
as the proportion of gases is about 1^ parts oxygen to 1 part 
acetylene for most purposes. If the oxygen is as great as 2.5 to 1 
of acetylene, an oxidizing flame will be produced, which will prob¬ 
ably cut the metal; if there is too much acetylene, it will split up 
or crack and allow carbon to enter the weld and carbonize it or 
make it hard. The flame should be adjusted so that the two cones 
formed in the flame unite into a single small one, and the tip of 
the white cone in the flame should just touch the metal. The hand 
must be held steady when working because if the tip of the torch 
should touch the work, it might cause a flash hack and necessitate 
relighting; if not, an explosion or something worse might happen. 

Oxy- Hydrogen Process. Oxy-hydrogen torches are handled 
similarly to oxy-acetylene torches, but when lighting it is necessary 
to turn the hydrogen on about two-thirds of the way and light it 
first. The oxygen should then be turned on enough to give a pale 
blue conical flame, and then the hydrogen should be turned on full. 
This wall take but a few seconds and should give a temperature 
of about 2800 degrees centigrade. The end of the cone of oxygen 
in the flame should never touch the work, as this would probably 
burn it. When through work, the oxygen should be turned off 
first. Theoretically, 2 parts of hydrogen should be used for each 
part of oxygen but experience shows that it is desirable to use as 
much as 3 parts of hydrogen in many cases, to prevent burning of 
the metal. A larger proportion of hydrogen is not necessary if 
the two gases are properly mixed in the burner. 

Gas=Welding Apparatus. General Features. The apparatus 
required for oxy-acetylene or oxy-hydrogen welding and cutting 
is very similar, consisting in either case of a supply of the gases; 
a suitable burner or torch; regulating valves; and hose for the 
connections. Beyond this, the differences are in details of the 
equipment only. Under the descriptions of the gases used for 


20 


AUTOMOBILE WELDING 


welding we have already learned something of the processes for 
their production and storage, but the gas generators are sufficiently 
different to warrant some further description. 

Acetylene Equipment. The acetylene generator is a com¬ 
paratively simple device, usually a single steel receptacle wdth 
compartments for holding the water, carbide, and gas, with various 
attachments for controlling its action. High-pressure systems are 
gradually being abandoned, and today the medium- and low- 
pressure systems only are in much use, with the low-pressure system 
of generation in the majority. After the gas is generated, however, 
it is compressed and stored at very high pressures. The best known 
system of acetylene storage and distribution is that of the 
Prest-O-Lite Company of Indianapolis, which consists of cylinders 
which can be bought or rented filled with acetylene ready for use. 

Acetylene is readily soluble in liquid acetone, which is cheap, 
inert, and incombustible; so storage cylinders are partly filled with 
it and the acetylene gas compressed into it. Owing to its peculiar 
nature, acetone will dissolve 24 times its own volume of acetylene 
at atmospheric pressure and at a temperature of 15 degrees centi¬ 
grade. At 12 times atmospheric pressure (180 pounds), it will 
dissolve about 300 times its volume of acetylene, and expand only 
abour 50 per cent when doing so. The cylinders are partly filled 
with asbestos fiber to carry the acetone, and it is merely necessary 
to charge them with compressed acetylene to fill them. When 
the necessary valves and gages are attached, the cylinders are 
ready for use, and when accompanied by similar cylinders filled 
with compressed oxygen and mounted on small trucks, as shown 
in Fig. 9, form good portable welding outfits for use in garages. 

Acetylene generators are made in five types, of which the drop 
type is most used. It is the most economical, and is arranged so 
that the carbide is fed into a hopper at the top and falls a few lumps 
at a time into a large vessel of water below. The carbide is not so 
good ground as it is in lumps, and the feeding mechanism is operated 
by the gas pressure in order to keep the supply constant. The 
water absorbs the heat generated by the chemical action, thus keeping 
the gas and the outfit cooler than with some of the other types. The 
gas bubbles up through the water and is washed, the lime remaining 
in the bottom where it can be reached for removal; this lime can 


118 




AUTOMOBILE WELDING 


21 


be used as a fertilizer. Theoretically, 1 pound of carbide requires 
h pound of water to make gas, but in practice it takes about 1 gallon 
of water to 1 pound of carbide for the best results. This should 
produce about 41 cubic feet of gas, with a loss of only about 3 per 
cent by absorption in the water. The attachments on the generator 
tank are usually a filter, flash-back chamber, drainage chamber, 
water filling tube, blow-off valve, and other devices required for 
connections, etc. Calcium carbide alone is not an explosive and 
will not explode when heated, but it will absorb moisture very 
rapidly and generate acetylene which is explosive and must, there¬ 
fore, be kept in air-tight cans. Acetylene is explosive at any point 
between the limits of 2 per cent gas and 98 per cent air up to 49 
per cent gas and 51 per cent air, so must be handled carefully. 

Oxygen and Hydrogen Manufacture. Oxygen generators are 
quite expensive and complicated, so it is best to buy compressed 
oxygen in cylinders instead of trying to make it unless the quantity 
required is very great. The same thing applies to hydrogen, but 
since they are both produced from water by the electrolytic 
process it will be worth while to consider the apparatus in a general 
way here. This process consists in passing a direct current of 
electricity at 2 or 3 volts pressure through a solution of sodium or 
potassium chlorate in water as the electrolyte, which produces 2 
volumes of hydrogen to 1 of oxygen. Since a direct current is used, 
oxygen arises from the water around the positive terminal and 
hydrogen from around the negative plate, each gas being conducted 
through separate pipes for compression and storage. The equip¬ 
ment usually consists of several generators in the form of tanks 
of cast iron, with a partition extending part way down in the center 
to divide the tank into two parts. One terminal is placed in each 
section and the temperature maintained at about 165 degrees 
Fahrenheit, because the work can be done at a lower voltage at 
this temperature than at any other. From 240 to 325 amperes 
of current are used, and the gases are about 99 per cent pure when 
made by this process. Purity is very important, because foreign 
matter in the gas may cause it to burn or spoil the weld. The 
apparatus for producing oxygen by the liquefaction of air is quite 
complicated and will not be discussed here; the other chemical 
processes are so little used they can be omitted also. 



22 AUTOMOBILE WELDING 

Torches. The torches or blow-pipes for gas welding, Fig. 11, 
and cutting, Fig. 12, are very important, and it was due to their 
imperfect development that prevented gas welding from being 
used a great many years ago. In general, torches for any system 


consist of a head or mixing chamber into which a suitable renewable 
tip can be screwed; two tubes to lead the gases to the head before mix¬ 
ing; valves for regulating the proportion of each gas; connections 
for the hose leading from the storage tanks; and a suitable handle 
for the torch. The torches are made as small and light as possible 
without sacrificing strength or safety, in order that the operator 
will not tire too easily through their use, and the hose should be 


t ^ 

ei | 
© 












AUTOMOBILE WELDING 


23 


small and flexible for the same reason. Wire gauze is placed inside 
|the torch to prevent the gases flashing back in case of too low pres¬ 
sure, and the tips are of various sizes to suit different kinds of work. 
Goggles for the operator’s eyes and gloves for the hands are also 
necessary. 

WELDING OPERATIONS 

Work to Be Done. A great many automobile repair shops 
are merely a part of a garage catering to people who desire to store 
their cars and purchase supplies, and such shops are not equipped 
to do more than the simplest of repair jobs and make adjustments. 

I Shops desiring to do any sort of L work which may come in must 
have the proper kind of equipment, and it is such shops that require 
welding apparatus of some sort. The work to be done will vary 
from welding a cracked side frame without dismantling, or a broken 
spring shackle, or steering knuckle, up to saving a cracked cylinder 
or crank case, welding a broken crank shaft, or other job requiring 
dismantling, or even practically rebuilding a car which has been 
almost ruined through a general smash-up. It is really astonishing 
to see how much can be done in shops having complete and up-to- 
date welding apparatus, and comparatively large amounts can be 
saved for owners while at the same time making large profits for 
the shops by such work. About the only thing it does not pay 
I to repair is a broken wire spoke in a wheel, if proper apparatus is 
t available. 

Qualities Required of Men. Qualities of Skill and Judgment. 
iThe art of welding with either gas or electric arc welding apparatus 
can be learned by most any good mechanic of average intelligence 
if he is sufficiently interested in his work to really want to become 
an artist, but it cannot be learned any quicker than any other line 
of work. Under the direction of an experienced instructor it will 
in most cases be possible to learn how to handle the torch or elec¬ 
trode holder and to apply the welding material to the joint within 
a week or two. After that it is a matter of several months of steady 
practice before the operator will become really proficient and be 
able to handle any sort of a job that comes along. This does 
not mean that welding is too hard for an average good mechanic 
to learn, but merely that it is not so simple as it appears after watch- 


121 





24 


AUTOMOBILE WELDING 


ing an expert do the work. In addition to learning how to handle 
the flame or arc and get the right heat, it is necesasry to know how 
to fuse the various metals without burning them; flow them into 
place without having them run away; work the filler and the metal 
of the job together so as to form a homogeneous weld; know when 
and when not to use flux; when to pre-heat; how to weld so as not 
to get hard spots in the work; and how to handle the work so it 
will not crack in cooling. It is also necessary to learn what jobs; 
it will not pay to try to weld and when it will be best to use the 
gas or the electric arc for the work. 

Ingenuity. The expert welder will never admit that a job 
cannot be welded unless he knows it will not pay to spend the time 
and money required to do it. One of the principal requirements] 
in a good welder is ingenuity, because there will be many times 
when a little careful planning will make it worth while to do a job 
which otherwise might be considered impracticable from the financial] 
standpoint. For example, if the broken article is a low priced 
piece and is in bad condition it will be better to replace it than] 
to try to save it—unless the car owner is in a hurry and a new part j 
is not available—whereas, if the piece is large or complicated and i 
expensive to replace it will nearly always pay to weld it. An 
ingenious operator will soon learn to decide such matters quickly,: 
develop new methods, reduce costs, and thus build up a good repu¬ 
tation for his shop which will result in increased business at good 
prices. 

All-Around Mechanical Training. There is no special kind 
of mechanical training that will fit a man for welding any better 
than any other kind, but as a sort of general rule it may safely 
be said that a good all around mechanic will probably be better 
equipped than any man who knows but one branch of his trade. 
The man who has had at least a little experience as a blacksmith, 
machinist, boiler maker, foundryman, engineer, and electrician is 
better equipped than a man who has had less experience, providing 
he has really learned something from his experience instead of 
being merely a restless wanderer from shop to shop. He should 
also have a good knowledge of the construction and operation of 
automobiles and other machinery, and also of the strength of mate¬ 
rials and their proper uses and limitations. 


122 


AUTOMOBILE WELDING 


25 


Equipment Required. Requirements in Small and Large Shops. 
Small repair shops or garages limiting themselves to the lighter 
kinds of jobs can get along with a comparatively small gas welding 
outfit of any reliable make; but larger shops should have electric 
arc welders, and the largest or most complete establishments must 
have both arc and gas welders to be really properly equipped to 
do all kinds of work most rapidly, economically, and conveniently. It 
will then be possible to use the process best suited to each job, 
or to do several jobs of different kinds at the same time. It is 
also desirable to have capacity for at least two men to work at 
once, no matter what system of welding is used, because large 
numbers of jobs can be done better if done quickly. 

Equipment Best Suited to Various Classes of Work. Small 
gas welders are good for welding light sheet steel, copper, brass, 
or aluminum, or small castings of the same metals. Small arc 
welders are better suited for medium and heavy steel plates, forgings, 
castings, and for other kinds of general welding work. Large gas 
welders are best for cutting, but may be used for medium or heavy 
welding work when the cost of operation is of no importance. Me¬ 
dium or large sized arc welders will be found best for heavy work, 
cast-iron welding, or in shops requiring more than two or three oper¬ 
ators, and may also be used for cutting. Electric arc welding is 
cheaper than gas welding for nearly everything excepting com¬ 
paratively thin sheet steel work and for articles of brass or bronze. 
Gas welders are cheaper to operate for light steel plates and for most 
of the cutting jobs to be done in automobile repair shops. Occa¬ 
sional exceptions to the above rules will be found, but in general 
they will hold to be true. This accounts for the rapidly increasing 
adoption of arc welders in automobile factories as well as repair 
shops. 

Small Equipment. In general, as has already been stated, 
iron and steel plates, castings, and forgings can best be welded 
with the electric arc, but non-ferrous metals like brass, copper, 
aluminum, platinum, gold, silver, etc., can best be welded with 
gas, hence it is preferable to have both kinds of equipment available, 
even though one of them be small. In addition to the welding 
machines it will be necessary to have the usual attachments and 
supplies, such as torches and hose, goggles, etc., which are a part 


123 



26 


AUTOMOBILE WELDING 


of all gas outfits; and the electrode holders and cables, face shields, 
etc., which come with arc outfits. Gloves of good buckskin are 
also desirable, and a kit of tools consisting of hammer, chisel, coarse 
and fine files, screw clamps of two to three sizes, pliers, hack saw, 
rule, and piece of chalk and waste will also be required. The tool 
kit will be increased in size as the operator becomes more experienced 
and has a great variety of work to do, but the foregoing will be a 
good start. 

In the shop there should be a good forge or a couple of medium 
or large sized torches for pre-heating large pieces before welding. 
This is especially true when preparing cast iron for welding and 
will be referred to later when discussing cylinder repairs. Vises 
on substantial benches; two or three pairs of strong “horses”; a 
good emery wheel; a separate space to work in, and plenty of good 
light are also essential to the best work. The space where arc 
welding is to be done should be screened off from the rest of the 
shop if a separate room is not available, because the arc is brighter 
than a gas flame, but if ordinary common sense is used there is no 
danger from the arc as has been claimed. The face shields. Fig. 3, 
will give all the protection required for the operators, and there 
are men using the arc who have done so for over 25 years with 
entire safety. Any additional equipment beyond that above 
enumerated will be valuable, of course, and a well equipped machine 
shop should also be available nearby (if not in the shop) so that 
many of the parts repaired can be machined before using, if neces¬ 
sary. This will always be necessary when repairing finished 
surfaces, such as the tops of crank cases, cylinder bases or lugs, 
shafts, etc. 

Kinds of Fillers to Use. As a general rule, it may safely be 
stated that the materials used in welding by any process should 
be similar to that composing the article to be welded. There are 
but few exceptions to this rule, the principal one being that it usually 
pays to use a filler containing an excess of those elements which 
pass off at high temperatures or which may be necessary to give 
added strength to the weld, if needed. In all cases it will pay to 
use only pure materials and the best obtainable regardless of cost, 
because a poor weld may not only have to be done over at a loss 
but may also injure the reputation of the shop doing it. There 


AUTOMOBILE WELDING 


27 


are several companies specializing in the supply of welding materials, 
|and in the best shops it is the rule to have everything tested or 
Analyzed before accepting it or using it. 

Effect of Various Substances in Welding Material. Some refer¬ 
ence has already been made to the effect of impurities in iron, under 
the heading “Methods of Pre-Heating”, but a few more words 
as to certain other conditions are also necessary. Carbon increases 
'the tensile or pulling strength of iron, but it also decreases its 
elongation or stretching before breaking and should be kept as 
{small in amount as possible in welding wire. Carbon also tends 
{to cause crystallization of steel under repeated shocks or vibration, 
{and also when heated and cooled frequently, with consequent 
[liability to become brittle and easily broken. Sulphur is a very 
(common impurity in welding materials and must be looked out 
for because it makes the metal brittle when hot, and causes it to 
crack easily if hammered while hot. Phosphorus causes large 
crystals to form in the weld when cooling, thus reducing the strength 
and making it break easier when cold. This has the reverse effect 
from sulphur and they both should be eliminated. Slag is also 
found in low grade welding materials and makes good, clean, reliable 
or homogeneous welds impossible. These impurities are not 
found in the best grades of genuine imported Swedish iron wire, 
hence this has become the universal welding material for all kinds 
of iron and steel plates, forgings, etc., and for many kinds of steel 
I casting welding. 

Preparation of Work. Before starting the welding operation 
proper, it is necessary to be sure that the piece is properly prepared 
to receive the filling material, that the parts are properly aligned, 
and that the weld can be carried through to a satisfactory conclusion. 

Small Pieces. Pieces of comparatively light section, such as 
steel plate , etc., of not more than J inch in thickness, may be welded 
by leaving a space between them of somewhat less than their thick¬ 
ness and filling in with metal by using the gas or metallic arc welders. 
If the sheets lie face to face and require welding along the edges, 
it will be sufficient to clamp them tightly and fuse down the edges 
with the gas or the carbon arc, or in some cases deposit metal with 
the metallic arc. If the plates are over f inch thick it will be neces¬ 
sary to bevel the edges of the joint to an angle of 30° to 60°, depend- 





28 


AUTOMOBILE WELDING 


ing upon the thickness, in order to provide space enough for the 
filler. An average case will require beveling each side to an angle 
of about 45° for butt welding the sheets edge to edge, and this 
will also apply to such parts as side frames, also. 

Large Pieces. Large pieces, such as forgings , castings , etc., 
must always be beveled sufficiently to insure making the weld 
the full thickness of the piece, and the amount of bevel should be 
great enough to allow plenty of room for easy work in order to keep 
down the cost of handling. When possible to work from both 
sides of the piece, beveling should be done on both sides before 
starting welding, thus reducing the amount of space required and 
the amount of filling to be done. Steel forgings need not be pre¬ 
heated if welded with the arc using the metallic electrode, but it 
is preferable to pre-heat if the work must be done with gas on account 
of the cost of gas used in bringing the piece up to welding heat. The 
same thing applies to steel castings of medium or small size, but 
large steel castings or cast-iron pieces should always be pre-heated 
before welding by any process. This not only reduces the time 
required to get the temperature up to the proper point for welding 
but also insures the piece being soft enough to machine after welding, 
and reduces the liability to crack when cooling after welding. It 
is also desirable to keep the piece hot while welding, so work must 
sometimes be done with the piece in a forge or temporary furnace,, 
especially large iron castings. This is not very pleasant for the 
operator, but such jobs are usually of short duration. 

Copper Alloys. Castings of any of the copper alloys , such as 
brass , bronze , etc., are best welded with gas, but require similar 
preparation to articles of iron or steel. Cracks or other joints 
should be beveled to allow access to the bottom of the space to 
be welded, and medium or large pieces must be pre-heated to reduce 
welding cost and time. Copper is a good conductor of heat, so it is 
usually necessary to heat the part quite thoroughly in order to insure 
a good weld. These materials may also be welded with the arc 
by using a graphite electrode, and in all cases the filler should be 
of the same composition as the piece. The principal difficulty 
met with in welding brass and other articles containing zinc, lead, 
and tin is that these elements burn out at a comparatively low 
temperature and leave the weld spongy or porous, consequently, 




AUTOMOBILE WELDING 


29 


especial care must be used to keep the heat as low as it can be and 
still fuse the metal. This is the principal reason for using gas instead 
of the arc for such materials, because the arc is so hot. 

Aluminum. Aluminum castings can be welded with either 
kind of apparatus, and the parts need not be beveled unless they 
are over \ inch thick because the metal must be fused with the 
flame, and only enough pure aluminum added to make up the losses 
and give a slight reinforcement! to the weld. Sheet aluminum 
should be welded with gas, and the joint need not be beveled, 
but great care must be taken to prevent burning the metal. 

Welding Materials for Filler. As already stated under the 
heading of “Equipment Required”, the filling material should 
usually be of the same composition as the material to be welded, 
but it will be well to consider that matter in more detail at this 
point and before starting to describe the various operations usually 
arising in automobile repair shops. For welding plates of iron or 
steel it is best to use pure iron, such as Swedish iron, or Norway 
iron (so called), as it will amalgamate or mix with the job and give 
a good weld practically every time. Alloy steels of various kinds, 
such as vanadium steel, manganese steel, chrome steel, nickel steel, 
etc., have been welded with similar materials but not with any 
very great degree of success. This is due to the fact that the metals 
used as alloys burn out at the welding temperature and leave the 
weld porous, or lie inert in the form of globules and spoil the weld. 
The same thing is true when trying to weld bronze alloys, such as 
phosphor-bronze, manganese bronze, etc., so it is quite important 
that the operator be sure of his metal before starting to weld it 
by any process. High carbon steel may be welded if the piece is 
not to be subjected to great strains because the material next to 
the weld will be weakened by the operation, but it will be all right 
in some cases where the metal has been used to give good wearing 
life if the weld is not made on the wearing surface. 

For welding articles of cast iron it is best to use new material, 
cast-iron rods containing about 2 or 3 per cent excess of silicon 
being best for this purpose, because they produce good grey iron 
in the weld and make machining easier if properly pre-heated. 
If the iron contains as much as 4 per cent of silicon, it will be even 
better for large jobs, because the silicon is reduced under the action 


127 



30 


AUTOMOBILE WELDING 


of the flame or arc. The presence of manganese is not desirable 
for cast-iron welding, and good flux should always be used if the 
castings are not of the very best grade. Gasoline engine cylinders 
are usually made of good grey iron, but even there it is well to use! 
powdered aluminum as a flux to insure good welds. Scrap material 
seldom makes a good weld, even for articles of brass or bronze ,j 
because you can never be sure of its composition. A small amount 
of aluminum will be helpful for welding copper alloys, and sometimes j 
a little phosphorus will help, but it should be put into the welding | 
rods by foundries knowing their business or trouble will usually] 
follow. To successfully weld copper requires a filler with enough ! 
phosphorus to completely de-oxidize the weld, because copper-j 
oxide forms very rapidly at the welding temperature of copper. 1 
When properly done, the weld should be invisible and of the same 
color as the rest of the copper, but unless the operator has had 
considerable experience with his welding apparatus it is better to 
braze copper and brass if possible. Aluminum should be welded | 
with pure aluminum, free from silicon, and new metal is necessary, j 

DETAILS OF SPECIAL WELDS 

After learning the preceding matter, the student desiring to 
become an expert welder by either the gas or arc processes must then 
practice in the use of the apparatus in order to apply the principles, j 
because after learning to use the apparatus the work has only begun. 
It is only by months of continuous practice at the work that any 
man can become really expert and able to do any sort of work 
which may come along. The action of the various metals under 
the action of the high temperature welding process is of the utmost 
importance, because similar pieces may act differently on account 
of the weather, drafts in the room, location on the automobile, 
variations in composition, welding process used, speed with which 
the work must be done, etc. So we will consider a series of typical 
repair jobs in detail, and determine the best procedure in each case. \ 

Welding Main Frames. With the exception of the “Franklin” 
car, automobile main frames are made of steel channels, either 
structural channels on trucks or steel plate pressed into channel 
form of irregular shape for pleasure cars. These channels vary 
from about J inch thick up to nearly f inch thick, and from 3 inches 





AUTOMOBILE WELDING 31 

deep up to 8 inches deep with flanges top and bottom, and should 
be treated in very much the same way as steel plates of similar 
thicknesses. That is, the crack should be chipped out on one side 
to form a groove into which the filler may be fused. Work will 
usually have to be done from one side only, because the job is in 
a hurry or there is too much dismantling required, and it is best 
to work from the outside of the frame if possible. The paint should 
be scraped off for about an inch each side of the joint and all grease 
wiped off with a little gasoline before starting work, otherwise 


Fig. 13. Welding Broken Frame of 5-Ton Automobile Truck with a Gs^ Torch 
Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 

it might get into the weld and spoil the work. Since most cracks 
or breaks occur in the side frames, instead of in the cross-braces, 
the work will generally have to be done by working against the 
vertical surface and the metallic arc welder is easier to use than gas, 
but gas may be used, as shown in Fig. 13, and the filler fused in 
if the operator is careful and starts work at the bottom and works 
upward. 

If the frame has started to crack from below, the first thing 
to do is to jack it up to bring the parts in line and close up the crack. 
Then chip it out as described so as to weld full thickness of the 


129 






32 


AUTOMOBILE WELDING 



Fig. 15. Truck Frame of Fig. 14 Repaired by Gas-Welding Outfit, 
Unengaged Parts Protected by Asbestos Paper 
Courtesy of Ox-weld-Acetylene Company, Chicago, Illinois] 


130 











AUTOMOBILE WELDING 33 

flange and web of the angle, and deposit enough metal to reinforce 
the stock until about double the original thickness. Chip, grind, 
or file smooth and paint. The reinforcement should be left on 
unless necessary to attach something at the point of repair. If the 
break comes at a hole in the frame, such as where a spring shackle 
is attached, it is usually best to weld the hole up and re-drill it. 
If some part has been torn off accidentally and made a large hole 
in the frame, a piece can be set in and welded all around the edges 
to tie it to the frame. Figs. 14 and 15 show a truck frame with 


Fig. 16. Broken Touring Car Chassis Ready for Welds 
Courtesy of C & C Electric and Manufacturing Company, Garwood, New Jersey 

a piece broken out of one corner and a new piece welded in place 
with oxy-hydrogen apparatus, made by the Oxweld-Acetylene 
Company, Chicago, Illinois. 

Sometimes a frame will break entirely through full depth, due 
to an accident or too heavy loading, and in such cases it will be best 
to weld a channel shaped reinforcing piece inside and tie the frame 
to it at the point of break. In this case, the new piece should be 
welded along the edges of both flanges and at the ends, and also 
through holes at intervals to tie the two pieces together as completely 


131 







34 


AUTOMOBILE WELDING 


as possible. When the flanges are broken it is also best to set a 
piece on the inside, and Fig. 16 shows a touring car that had the 
engine torn out accidentally in such a way as to rip pieces out of 
the flanges on both side frames. Channel shaped steel pieces were 
set inside the frames and welded in with the metallic electrode, 
the breaks in the flanges filled in flush and new holes drilled. 
Fig. 17 shows the finished job ready for drilling engine bracket 
holes, and a job of this sort can be done in about a half day at a 
cost for labor, material, and electric power of $2.00 to $3.00, depend- 



Fig. 17. Frame of Fig. 16 Repaired by Electric Welding Outfit 
Courtesy of C & C Electric and Manufacturing Company, Garwood, New Jersey 


ing upon the cost of current. The usual charge for this work is 
from $10.00 to $15.00, whereas a new frame will cost in place $50.00 
to $75.00 on account of the labor of dismantling and assembling 
everything on the car. A similar job done with gas will cost from 
$4.00 to $6.00 in most shops. 

Welding Running Gear. Rear Axles and Housings. The 
running gear of an automobile usually gets a large share of abuse, 
so any weaknesses are bound to develop there in a short time if 
they exist. Rear axle housings are now made in various ways of 
pressed steel parts welded together, and if the work is not well 


132 









AUTOMOBILE WELDING 


35 


done or the parts too light there will be trouble. If the entire 
housing breaks in two, as indicated in Fig. 18, it must be lined up 
and clamped in position, chipped out along the crack to get room 
for welding and then filled in with enough reinforcement to insure 
the required strength, Fig. 19. This is a rare happening and is 



Fig. 18. Broken Rear Axle Housing 
Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 


usually the result of a bad smash-up, but where the housings are 
not properly welded along the edges, as shown in Fig. 20, there is 
considerable liability of the seam opening up under the vibration 
met with in service. In such cases it is necessary to chip out the 
joint full length and re-weld. This sort of job has been done with 
the greatest success by using the metallic electrode arc welding 
process, using a | inch wire and about 120 amperes and depositing 



Fig. 19. Rear Axle Housing of Fig. 18 Repaired by Gas Weld 
Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 


the joint full, as shown in Fig. 21. The work will be smooth enough 
to paint over, and such a job should not cost over $1.00, although 
the charge to customer would be $3.00 to $5.00. 

Front Axles. Front axles are usually of steel forgings and 
seldom break, but in such an event they are easily welded because 


133 


36 


AUTOMOBILE WELDING 


steel is one of the easiest metals to weld. The pieces should be 
ground or chipped each side of the break and on each side of the 
piece to give two grooves in which to weld, and may be welded 
with either gas or the metallic arc. If the axle is out of the car, the 
gas will be all right; but if in position on the car, the arc will probably 



Fig. 20. Open Seam and Cracks in Fig. 21. Housing of Fig. 21 Properly- 

Welded Housing Welded by C & C Outfit 

be more convenient and consequently cheaper to use. This is 
another kind of job where it will be best to build up metal at the 
weld in order to give added strength, because the filling material 
will probably not be so strong as the original forging. Vanadium 
steel wire should be good for this purpose, although Swedish iron will 



134 








AUTOMOBILE WELDING 


37 


do if carefully handled and thoroughly amalgamated with the job. 
Fig. 22 shows a broken axle and Fig. 23 shows it welded. A job 
like this can be done for about SI.00 and should bring 13.00 or 
$4.00 to the shop. 

Miscellaneous Rigging. Brake, rigging and similar parts some¬ 
times break and can be easily welded because they are usually 



Fig. 22. Broken Front-Axle Forging 
Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 


easy to remove and simple in shape. Most of them are small 
forgings, but if made of cast steel or iron they may be welded just 
the same. Such articles will not require pre-heating, but should 
be beveled at the break before welding. Fig. 19 shows a number 



Fig. 23. Front Axle of Fig. 22 Gas Welded Ready for Use 
Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 

of small castings welded with the arc, using a graphite electrode 
and fusing the metal into place, and the entire lot were welded in 
an hour and a quarter at a total cost for labor, current, and material 
of $1.05 for the 18 pieces. A J-inch graphite electrode was used, 
and the work done with 150 amperes at 70 volts. A fair charge 
for such work is $9.00. Spring leaves may also be welded to help 



38 


AUTOMOBILE WELDING 



?-— 





- -N " .,<• ■ - \ 






5 :<! !WSSB!ini" 1r1 [mM 

& -’IT 




K 

»$ s s , 

*■$%* > . t >>- 

'..-x ‘ . '*• 

1 

•• 












136 


Fig. 24. Eighteen Forgings Electrically Welded at Total Cost of $1.05 for Labor, Current, and Material 

Courtesy of C & C Electric and Manufacturing Company, Garwood , New Jersey 










AUTOMOBILE WELDING 


39 


out in case of an emergency, but of course will not be so elastic as 
before. It pays to try it, however, in many cases because a large 
number of the breaks occur at the center of the spring where it 
rests on the axle, and this makes it possible to add a plate below 
to help stiffen the spring. Welded springs sometimes give as good 
service as new ones, so it is worth trying. The work is done in 
similar manner to any other steel plate welding. Steel rims have 
also been welded by both the gas and arc processes and are very 
successful. Similarly, small tubing in connection with the water 



Fig. 25. Miscellaneous Pipe Welds with Light Tubing 
Courtesy of C & C Electric and Manufacturing Company, Garwood, New Jersey 


circulating system similar to the samples shown in Fig. 25 can be 
welded successfully. 

Welding Crank Cases. Aluminum Crank Cases. Under this 
heading would naturally be included the engine crank cases, of 
iron, steel, or aluminum, and transmission cases. Aluminum crank 
cases are usually of castings and have been welded by both the gas 
and arc processes, but the gas process seems to give the best results 
on account of the ability to control the heat easier. However, 
great care must be taken to be sure the metal is not oxidized by 
the flame and ruined. The arc does not tend to oxidize so much 
and is being used more than formerly on that account, as well as 
the lower cost in most towns. The edges of the break must be 
carefully cleaned, and chipped if the part is over J inch thick, 
Fig .26, and the new pure aluminum fused into place, Fig. 27. The 






40 AUTOMOBILE WELDING 

flame or graphite arc, whichever is used, must be handled so as 
to fuse the metal each side of the weld into place with the new 
metal or there will be no joining of the filler with the metal of the 
piece. Since this is really a sort of “puddling” process, it is neces¬ 
sary to have the piece in a horizontal position where working in 


order to keep the molten metal from running out of the joint. In 
most cases it will be advisable to build up a mold or dam around 
the joint to hold the metal in place, and this can be of clay or other 
luting for gas welding but should be of powdered graphite mixed 
with silicate of soda (water-glass) for arc welding. The metallic 


electrode cannot be used for welding aluminum. Work of this 
sort is not cheaply done and usually the charges are in proportion 
to the value of the piece saved by welding. 

Cast-Iron Crank Cases. Cast-iron crank cases or transmission 
cases can be welded as easily as any other cast-iron piece, but must 


Fig. 26. Broken Aluminum Crank Case 
Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 


Fig. 27. Aluminum Crank Case of Fig. 27 Welded by Gas Outfit 
Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 


AUTOMOBILE WELDING 


41 


also be welded with the piece in a horizontal position. Either the 
graphite arc or the gas process may be used, but the joint must be 
chipped out and the piece pre-heated before welding. It will pay 
to try to save most any kind of a crank case by welding, because they 
are expensive, there is considerable machine work on them, and they 
are usually a long time coming from the factory. This is another 
instance where the charges are in proportion to the value of the 
article and the delay of getting new ones. As a general rule, it 
may be said that the actual cost of welding such pieces will be about 
$1.00 an hour for electric welding and about $1.50 for gas welding. 
If the case is of pressed steel, like the Ford cases, they can be handled 
the same as any other sheet steel article. A common repair is to 
rivet the brackets again onto Ford crank cases, and the charge is 
! from 75 cents to $1.50 for the job. These brackets can be welded 
I on with the metallic electrode for 8 cents each and will never again 
come off. 

If the arm which supports the engine in the car frame should 
break off, it can readily be welded together by removing from the 
car and preparing by beveling all around and welding with a good 
reinforcement. In most instances it will not be an objection to 
have the extra metal at the joint. Extra ribs may be welded onto 
arms or other parts, and bosses built up for drilling and tapping 
new holes in the crank cases, etc. 

Welding Steel Shafts. Crank Shafts. Gas engine crank shafts 
are usually steel forgings of irregular shape and quite expensive, 
so it nearly always pays to try to save them by welding in case of 
breakage. If the break is due to the shaft being too light for its 
work, the only thing to do is to have a special shaft forged out of 
stronger material and then finished up to fit the engine, but in most 
cases the shafts break on account of accident or other unusual 
strain and are worth welding. If the break comes in a bearing it 
will not be possible to reinforce the shaft, but if outside of a bearing 
or in the crank there is nearly always room to build it up some in 
size. This is desirable to prevent another break occurring at the 
same place. In jobs of this sort it is best to set the shaft up in a 
lathe with steady rests at frequent intervals to support it in order 
to insure the parts being in absolute alignment. The joint to be 
welded must be beveled, of course, and the work may be done 


139 






AUTOMOBILE WELDING 


42 

by fusing soft steel into place with gas or by using the metallic 
electrode with the arc process. If the break is in the round part 
of the shaft, Fig. 28, the ends each side of the break should be turned 
off cone shaped and the weld made by working all around the shaft. 
If broken in a crank it should be beveled from each of the broad 



Fig. 28. Broken Automobile Motor Crank Shaft 
Courtesy of C & C Electric and Manufacturing Company, Garwood, New Jersey 


sides to the middle so the work can be done at the smallest depth. 
Pre-heating will not be necessary on a job of this kind, and a weld, 
such as is shown in Fig. 29, can be done in about an hour and a half 
with the arc, at a cost of about $1.00 to $1.25, and should bring the 
shop from $12.00 to $15.00. 

Drive Shafts and Axles. Drive shafts and rear axles are also 
readily mended by either process and should be handled in a similar 



Fig. 29. Automobile Crank Shaft of Fig. 28, Welded with Electric Arc-Welding Outfit 
Courtesy of C & C Electric and Manufacturing Company, Garwood, New Jersey 


manner to crank shafts. If the drive shaft is of steel tubing with the 
end forgings welded on, as is the usual construction, and should be 
broken through the tubular portion, the best way to weld it will be to 
bevel the ends of the tube at the break, shrink the tubes onto a 
machine steel rod of proper size and about three inches long, and then 
weld the tubes and rod together with the metallic electrode. Jobs of 












AUTOMOBILE WELDING 


43 


this sort can be welded for about two cents, exclusive of the cost 
of preparation of the parts, or a total of about 50 cents, and are 
worth $1.50 each. 



Fig. 30. Broken Block Cylinder Casting with Jacket Cut Away 
to Allow Proper Repair 

Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 


Welding Engine Cylinders. Studying the Break. One of the 
commonest jobs arising in automobile repair shops is the welding 
of cracked engine cylinders, especially in the winter when people 
are careless about allowing their cooling water to freeze and crack 
the water-jacket. These cracks may be in the cylinder heads and 



Fig. 31. Cylinder Casting of Fig. 30 Welded and Jacket Also 
Welded Back in Place 

Courtesy of Oxweld-Acetylene Company, Chicago, Illinois 


necessitate cutting away a part of the jacket, Figs. 30 and 31, to 
give access to the break, or they may merely appear on the outer 
wall of the jacket and be easily handled. If the crack is on the 


141 




44 


AUTOMOBILE WELDING 


inner side it will be necessary to cut away the outer wall with an 
oxy-acetylene torch, weld the crack, and then re-weld the outer 
patch in place again. In such a case it will be necessary to examine 
the casting carefully to see where the parting ribs come inside of 
the water jacket, both with relation to the crack and to the various j 
openings and bosses on the outside, before it will be safe to start 
work. Then the smallest hole possible should be cut in the outer 
wall of the jacket through which to work, and the edges of the crack 
chipped and cleaned ready for filling in. The entire casting should 
then be carefully and slowly pre-heated to a dull red heat in a good 
forge or furnace, with a fairly bright red heat at the point to be 
welded. The work can then be done with a gas torch or with the 
graphite electrode arc by puddling in new cast iron containing a 
little extra silicon, as already described, and must be done in a 
horizontal position. The patch can then be welded in the outside 
in a similar manner, and the casting allowed to cool slowly by being 
covered up with some good heat insulator or left in the furnace 
until it all cools off. 

Block Cylinders. When handling single cylinders the job is 
comparatively easy, but in these days of block castings it is not so 
easy to do welding without the most complete equipment one can 
afford. These large and complicated castings require great care 
and careful consideration, but can be welded successfully and at 
considerable profit if handled right. Here is where a man with a 
little foundry experience will be able to go about his work a lot 
more freely than a man with no knowledge of how castings act when 
at a bright red heat. Iron cylinder castings should be annealed at 
the foundry when made, or before machining at the factory, and 
should therefore not be drawn out of shape by the pre-heating 
process when welding. If it is found that the casting is warped 
by pre-heating, the only thing to do is to get a new one. If the 
job is one which looks bad to do, or the shape and size of the casting 
are such as to cause any doubts regarding the success of the operation, 
it is best to explain the matter fully to the customer and undertake 
the job only at the customer’s risk. In most cases, however, it 
will be safe to undertake the repair and no trouble should ensue if 
the work is properly done. Where the job consists of welding on a 
broken lug or foot it is comparatively easy, and after chipping or 


142 






AUTOMOBILE WELDING 


45 


grinding the edges of the joint the casting should be heated around 
the spot to be welded and then filled in. Care should always be 
taken to see that the lugs line up properly with the rest of the casting, 
if there is any finish on the parts or something is to be attached to 
them, and a slight reinforcement should be added if possible. 

Costs. The cost of welding cylinders ranges from $1.00 to 
$3.00 for cracks in the outer walls of water jackets, when done by 
either process, and the charges run from $2.00 to $5.00 for the work. 
When the crack is through the inner wall, the cost is from $3.00 to 
$10.00, depending upon the kind of casting and size and location 
of crack, and the charge should be from $5.00 to $20.00, according 
to the value of a new casting and the amount of dismantling required, 
etc. In most instances the work will cost somewhat less when done 
with the graphite electrode, in towns where current costs not more 
than 3 cents per kilowatt hour, than when done by the gas process. 
Welding on lugs costs from 25 cents up to $1.00 and brings from $1.00 
to $5.00, depending upon circumstances. The matter of charges 
for work done on engine cylinders is a big problem, because the 
amount of work done in addition to the mere welding operation 
may be very much greater than that in connection with the weld 
alone, and this will frequently be of more importance in determining 
the price than the cost of the weld. If it is necessary to re-bore 
the cylinder, the charge must be in proportion. 

Welding Body Parts. The tendency to return to the use of 
sheet aluminum for touring cars, limousines, runabouts, and other 
kinds of bodies, may result in calls upon repair shops to weld such 
materials, and it can be done with gas-welding outfits. Most cars 
now in service, however, have their bodies made of sheet steel 
and this may be welded with either the gas or the metallic electrode 
process. Where the framework of the body is of steel angles, the 
sheets can be welded thereto in place of riveting and a very good 
job done, but if the framing is of wood the only thing to be done is 
to weld the joints in the sheets. Welding done on bodies will always 
spoil the paint for a considerable distance around the weld, and if 
the plate is heated too much it will wrinkle. Electric arc welding 
presents some advantages over the gas for this work on that account, 
because the arc is localized when using the metallic electrode and 
the work is done so quickly and the arc moved along to another 


4G 


AUTOMOBILE WELDING 



spot before the heat can spread very far around the weld. It is 
also easier to work against vertical surfaces or overhead with the 

metallic electrode, although this 
is being done with gas-welding 
apparatus successfully now. 

Mud guards frequently come 
to grief against the sides of garage 
doors, other automobiles, wagons, 
etc., and require welding, and 
this can be done as easily as any 
other sheet-metal work. It is 
not necessary to bevel such thin 
material, although the paint 
should be removed from near the 
joint; by placing a block of steel 
along the upper surface and 
welding from the other side with 
a metallic electrode, the finished 
surface can be left in such smooth 
condition as to require very little 
finishing before painting. If the 
brackets supporting the guards 
are broken, they can be welded 
as readily as any other forgings, 
and this operation has been de¬ 
scribed. The bonnets can be han¬ 
dled as other sheet-metal parts, 
and leaky radiators should be sol¬ 
dered as usual as it does not pay 
to try to weld them. Piping of 
iron or steel, such as exhaust 
manifolds and pipes, mufflers, 
etc., are readily welded according 
to the principles already laid 
down for other parts of similar 
materials, and gears should be welded like other forgings, Fig. 25. 
A gasoline storage tank with electrically welded seams is shown 
in Fig. 32. 


Fig. 32. Electric Arc-Welded Gasoline 
Storage Tank 











AUTOMOBILE WELDING 


47 


GENERAL WELDING DATA 

Sources of Information. In addition to the general informa- 
; tion given in the foregoing pages regarding the applications of the 
various systems of welding, it will be necessary for the student of 
this subject to know various other facts in order to be fully informed 
i on the matter. In addition to Tables I to VI, it will be well for the 
| beginner to get copies of catalogues from the makers of the different 



Fig. 33. Methods of Making Welded Seams in Tanks 
Courtesy of C & C Electric and Manufacturing 
Company, Garwood, New Jersey 


kinds of welding equipments and become familiar with the details 
of the apparatus and learn all the main facts given as to the uses 
of the devices. After starting to use any sort of a welder it will be 
wise to write to the makers occasionally and ask questions concern¬ 
ing difficulties arising in the course of the work. If it is not possible 
to do this, then write direct to us and we will help you in any way 
we can to solve your problems. 


145 


































48 


AUTOMOBILE WELDING 



Strength of Welds. Unless a weld is strong enough for its 
purpose, it is a failure and represents a loss of time and money, so 
it is important to know what to expect when starting a job in order 
to put on a reinforcement if necessary. It is well known that a 
casting is not so strong as a forging or plate of the same material, 


hence, when a weld is made, it will not be so strong as the original 
piece unless made larger in section. Welds made in steel plates 
can be made nearly as strong as the plate, the rule being to get 
from 90 per cent to 95 per cent of the original strength at the same 
thickness, and the relative strength will be greater for thin plates 
than for heavy ones. This is due to the fact that thin plates can be 
welded by going along the seam once only, whereas thick plates 
require going over the seam several times to fill in and this increases ^ 


Fig. 34. Welded Steel Plates, Showing Strength of Welds 
Courtesy of C & C Electric and Manufacturing 
Company, Garwood, New Jersey 


146 












AUTOMOBILE WELDING 


49 


the liability of slag forming in the weld or imperfect fusion taking 
place with consequent reduction of value. The plate welds shown in 
Fig. 33 show how the seams are handled in tank work. 

In order to determine the relative strength of butt welded 
joints made with the arc using metallic electrodes, a series of plates, 
Fig. 34, were tested with the following results. Plates welded with 
gas would probably show similar results, and the relative costs 
would be about as given in Table I. 


TABLE I 


Strength of Butt=Welded Joints 


Plate 

Thickness 

(in.) 

Elastic Limit 
( lb. per sq. in.) 

Tensile 
Strength 
( lb. per sq. in.) 

Elongation . 
(per cent in 8 in.) 

Efficiency 
( per cent) 

i 

40930 

54650 

04.5 

97.6 

1 

44930 

53020 

05.75 

94.7 

1 

2 

40160 

51280 

04.75 

91.6 


The data in Table I was made from tests on plates with a nom¬ 
inal ultimate strength on 56,000 pounds per square inch on tensile 
pull, and is a fair example of what should be expected in ordinary 
cases. The elongation in the weld will always be less than in the 
original stock because the joint will be really a casting, but its ductil¬ 
ity can often be improved by hammering before it cools enough to 
lose color. 

The question of the relative values of various methods of form¬ 
ing joints is sometimes hard to answer, so another series of tests 


TABLE II 

Relative Strength of Joints 


Samples and Preparation 

Breaking 

Strain 

(lb.) 

Length After 
Breaking 
( in.) 

Effciency 
( per cent) 

Original piece of steel plate 

Lap joint, arc welded 

Lap joint, riveted and welded 
Butt joint, arc welded 

Butt joint, acetylene welded 

Lap joint, riveted only 

58,600 

54.800 
54,200 

47.800 

36.800 
35,000 

8.80 

8.94 

9.22 

8.28 

8.23 

100.00 

93.5 

92.2 

81.6 

62.8 

59.7 















50 


AUTOMOBILE WELDING 


was made to give something definite to go by and this result is shown 
in Table II. These figures are averages only, and experience shows j 
considerable variation above and below these figures in many cases. I 
The butt joints broke through the welds in both cases, the riveted 
plate broke through the rivet holes, and the others broke outside j 
the welds entirely. For most purposes in automobile work a butt 1 
joint will be necessary, but a lap joint or one made with a plate 
each side will be stronger, although a butted joint with some 
reinforcement will usually be all right. In all cases a great deal 
will depend upon the care with which the work is done. 

Effect on Composition of Welds with Arc and Gas. Something 
has already been said regarding the composition of the welding 
materials required for various purposes, and Table III will show 
the effect on steel plates when welded by both the gas and the elec¬ 
tric arc processes. 


TABLE III 


Analysis of Welded Steel Plate 



Electrically Welded 

Acetylene Welded 

Elements 

Unwelded 
Metal 
(per cent) 

Welded 
Joint 
(per cent) 

Unwelded 
Metal 
(per cent) 

Welded 
Joint 
(per cent) 

Silicon 

Carbon 

Sulphur 

Phosphorus 

Manganese 

Iron (by difference) 
Totals 

0.009 

0.15 

0.025 

0.068 

0.64 

99.108 

0.003 

Trace 

0.020 

0.043 

0.27 

99.664 

0.009 

0.15 

0.085 

0.068 

0.49 

99.198 

0.002 

Trace 

0.071 

0.067 

0.34 

99.520 

100.000 

100.000 

100.000 

100.000 


It will be seen that the silicon is reduced by welding much 
more than the other contents, although all are reduced somewhat. 
The percentage of iron increases, due to the reduction of the other 
elements, but the actual amount is the same after as before welding. 
In both cases the carbon was practically entirely burned out, and 
the arc reduced the phosphorus more than the gas flame. 

Costs of Welds by Arc and Gas Methods. The relative costs 
of gas and arc welding on steel plate work are about the same on 













AUTOMOBILE WELDING 


51 


light metal, but the arc is somewhat cheaper on heavy work on 
account of the gas used in keeping the plates warmed up to the 
proper temperature. For small shops doing but little repair work 
the cost of the work is not so important as the first cost of the appa¬ 
ratus, and for them a small gas welder will be all right, but large 
shops working on something all of the time must consider the cost 
of operation instead of merely the first cost of apparatus. Tables 
IY and Y give some reliable figures on both electric arc and gas 
welding, these figures being supplied by makers and users of both 
kinds of apparatus. In both cases the labor is figured at 30 cents 
per hour, electric power at 2 cents per kilowatt hour, acetylene at 
1 cent per cubic foot, and oxygen at 3 cents per cubic foot. 


TABLE IV 


Time and Cost of Electric Arc Welding 


Metal 

Thickness 

(in.) 

Average 

Current 

(amp.) 

Size 

Wire 

(in.) 

Average 

Speed 

(ft. per hour) 

Approx. Cost 
per Foot 

■h 

15 to 25 

i 

16 

22 

0.0175 

*to A 

25 to 50 

3 

32 

20 

0.0225 

A to * 

50 to 80 

T2 

18 

0.0275 

1 to Y6 

80 to 110 

1 

8 

16 

0.035 

Ato i 

110 to 130 

1 

8 

14 

0.0475 

A to _5_ 

4 LO 16 

130 to 150 

5 

32 

11 

0.075 

T6 ^0 | 

150 to 165 

5 

32 

8 

0.105 

I tO 1 

165 to 185 

5 

32 

6 

0.14 


TABLE V 

Time and Cost of Oxy=Acetylene Welding 


Metal 

Thickness 

Acetylene 
per Hour 
( cu. ft.) 

Oxygen 
per Hour 
( cu. ft.) 

Average 
Speed 
( ft per hour) 

Approx. Cost 
per Foot 

i 

2.7 

3.5 

40 

0.0085 

] 1 } to ■gTj 

4.5 

5.7 

32 

0.0175 

■§2 tO i 

7.5 

9.7 

25 

0.0275 

f to & 

10.5 

13.0 

19 

0.05 

11 } to 4 

14.0 

18.0 

14 

0.08 

J to ^ 

18.0 

23.0 

10 

0.12 

Ye to f 

-24.0 

30.0 

7 

0.22 

t to ^ 

32.0 

42.0 

5 

0.375 


Tables IV and V can be used with a fair degree of safety when 
figuring any sort of straight seam work, such as building gasoline 



















52 


AUTOMOBILE WELDING 


tanks, but do not include the cost of handling the pieces preparatory 
to welding. This is an item which will vary in different shops on 
account of the facilities available and the great differences in over¬ 
head expenses or fixed charges. For repair work the cost of getting 
ready may easily be more than the cost of doing the job, so experi¬ 
ence alone must be the guide in making estimates on such work. 

Cost of Cutting Jobs. When doing cutting with the electric arc, 
using a graphite electrode, work can be done at nearly one square 
inch of cross-section per minute for each 100 amperes used in the 
arc. Cutting with gas is much more rapid but is just about the 
same in cost on account of the great amount of oxygen used for this 
operation. Table VI gives the costs of gas cutting. 

TABLE VI 

Cost of Gas Cutting per Foot 


Thickness of 
Steel 
( in.) 

Oxygen 
( cu. ft. per ft.) 

Acetylene 
( cu. ft. per ft.) 

Time 

(min. per ft. cut) 

Total Cost 
( per ft. cut) 

1 

8 

0.45 

0.12 

1.00 

1.25 

1 

4 

0.50 

0.13 

1.00 

1.35 

5 

16 

0.60 

0.13 

1.00 

1.5 

3 

8 

0.90 

0.18 

1.25 

2.1 

1 

2 

1.30 

0.19 

1.25 

2.7 

4 

2.50 

0.25 

2.38 

4.6 


Table VI is based on oxygen at $1.50 per 100 cubic feet, labor 
at 35 cents per hour, and calcium carbide at 3 J cents per pound, and 
is based on straight cutting. For complicated work it will cost 
more. 

When welding long seams in sheets it is necessary to allow for 
the shrinkage of the filling material, and this should be done by 
spreading the edges of the sheets farther apart at the end to be 
welded last than at the starting place. In the sketch. Fig. 35, is 
shown the idea; the opening should be about 2\ per cent of the length 
of the seam. When welding with gas the work should progress 
away from the operator, and when using the arc it is better to work 
toward the operator. The welding rod must touch the work when 
welding with gas, whereas it must be kept away from contact with 
the work when using the metallic arc or the arc will go out and the 
rod stick to the job, but graphite work is done similar to gas weld- 









AUTOMOBILE WELDING 


53 



P-i bfl 


IS 





2 

* 

M 

0 



g 8 
a 3 - 1 

o* 

fl 

.2 

o 

P-i 


151 

























54 


AUTOMOBILE WELDING 


ing. Gas welding should be done by giving the flame a rotary 
motion by moving the torch around over the work, but for metallic 
electrode work the hand should be held steady and progress straight 
along the seam. If blowholes appear on the surface of welds being 
made with the graphite arc or with gas, they can be filled in by 
fusing the metal down; but if bad spots appear when using the 
metallic electrode, they must be chipped out and re-welded. The 
metallic electrode is always depositing metal, but the graphite arc 
and the gas flame are always melting it. These and other points 
will soon be learned by the operator, but are mentioned here to 
emphasize them and forestall trouble as much as possible. As the 
operator gains in experience, he will see many other things it is not 
possible to cover here but which will be very valuable in his work. 

CHEMICAL WELDING 

In the early part of this article, chemical welding was men¬ 
tioned as the third form of welding. This is almost exclusively 
made use of by the Goldschmidt Thermit Company of New York 
City. While, as before stated, this method is generally con¬ 
fined to large subjects such as immense crank shafts, cast-iron lathe 
beds, etc., yet it is not out of place to give here a very brief treat¬ 
ment to this form of welding. 

Thermit Welding. Welding by the thermit process is really j 
“cast welding”, because it is accomplished by pouring “thermit 
steel” around the parts to be joined. The main difference between 
this and other methods of cast welding lies in the method of produc¬ 
ing the molten metal. The name for the process is derived from the 
Greek word therme, meaning “heat”, and signifies that it is a heat 
process of welding or that the metal is produced by heat. The 
name was originally adopted as a sort of trade-mark but has come 
to be accepted as the name of the process. 

Chemical Reactions in Thermit Welding. The thermit weld¬ 
ing process is based upon a long series of experiments carried on for 
a number of years by various physicists and metallurgists to find 
some method of reducing metals readily from their oxides and ores. 
It is the direct result of the work done by Dr. Goldschmidt of 
Essen, Germany, in what is now the new field of aluminothermics, , 
and is based on his discovery that if finely divided metallic oxides 


152 


AUTOMOBILE WELDING 


55 


are mixed in certain proportions with finely divided aluminum they 
will, if ignited, fuse and produce a temperature of 5400 degrees Fahr¬ 
enheit in less than 30 seconds without the use of heat or power 
from the outside. The high affinity of aluminum for oxygen will 
cause it to draw the oxygen from the metallic oxide, combine with 
it to form aluminum oxide, raise the temperature of the mass by the 
violent reaction, and set the metal free. The greater weight of the 
metal will cause it to flow down through the mass in the container 
and the aluminum slag will rise to the top. 

For ordinary commercial welding purposes in machine shops 
and foundries, iron oxide is used and the reaction takes place accord¬ 
ing to the equation 

Fe 2 0 3 +2A1 = 2Fe+Al 2 0 3 

The liquid steel produced by this process represents one-third of the 
original material by volume and one-half of the original mixture by 
weight, the balance being lost as slag. This method of cast welding 
was developed about the year 1900, and the peculiar reaction used 
has also been applied to the production of numerous kinds of alloys 
and metals free from carbon. Further reference will be made to 
this. 

Analysis of the Composition of Thermit Steel. According to 
data furnished by the makers of thermit-welding apparatus the 
average analysis of thermit steel is as follows: 

Carbon.0.05 to 0.10 

Manganese.0.08 to 0.10 

Silicon.0.09 to 0.20 

Sulphur. .0.03 to 0.04 

Phosphorus...0.04 to 0.05 

Aluminum.0.07 to 0.18 

0.36 to 0.67 

The balance of the mixture is iron. 

Method of Starting the Reaction. During the experiments leading 
to the development of thermit welding, the mixture of metallic 
oxide and aluminum was heated from the outside to start the reac¬ 
tion, but finely divided aluminum will not melt at the temperature 
of cast iron and it was necessary to heat the mass so high that when 
action started it resulted in an explosion. So Dr. Goldschmidt used 


153 










56 


AUTOMOBILE WELDING 


a storm match to ignite a fuse of barium peroxide (BaO), which in 
turn ignited the mixture and started the reaction. 

Equipment for the Process. The apparatus required for thermit 
welding consists of a crucible, tripod, pre-heater, yellow wax, and a 
spade, with which there must also be used perishable materials con¬ 
sisting of thermit, manganese, molding material, and ignition powder.; 
The shell of the crucible is of sheet iron and it is lined with mag¬ 
nesia in order to stand the high temperature and has a magnesia! 
stone thimble at the bottom through which the metal flows. The 
process of preparing the lining is rather elaborate and must be care¬ 
fully done or the life of the crucible will be greatly reduced. The i 
tripod is used to support the crucible above the work, and the pre¬ 



heater is a combination compressed air and gasoline outfit used to 
heat the article to be welded in order that it may not chill the filling 
material. The wax is for forming the space to be filled when welding 
and about which a mold is made. It is melted out of the mold 
before welding. 

Preparing the Mold. The process of preparing the crucible 
and the mold are the principal features of the entire operation of 
thermit welding, as the mere act of casting the weld is compara¬ 
tively simple. The crucible is a sheet-iron shell with a hole below 
for the metal to pass through. It is to be lined with magnesia, 
carefully packed while hot enough to be plastic, and with a mag¬ 
nesia stone thimble at the bottom to form a bushed hole and protect 


154 






















AUTOMOBILE WELDING 


57 


the crucible. The magnesia lining should be put into place slowly 
and carefully and tamped tightly into place, for its value depends 
largely upon how hard it is packed. The lining is formed around 
a matrix to shape the hopper-like center and must be baked at a 
dull red heat for six hours before it is ready to use. A crucible will 
withstand about 20 reactions if well made, and must then be relined. 
The thimble must be placed in the bottom of the crucible so as to be 
removable. 

Construction of Mold. The construction of the mold is really 
the most important part of the operation, because upon this depends 
the amount and application of the filling material. The container 
or flask is usually made of steel plates placed so as to form a box 
| around the part to be welded, and then filled with the clay, etc., of 
the mold, the plates being fastened with bolts, tie-rods, clips, or 
clamps of whatever sort may be available, Fig. 36. The first step 
in the formation of the mold is to build a collar of the yellow bees- 
j! wax around the place to be welded, making this of the size and 
shape desired for the weld. After the collar is formed, the flask is 
placed around it and filled with a mixture of ground fire brick, fire 
clay, and fire sand in equal parts. There must be three channels 
in every mold, a pouring gate, a riser, and a heating gate. The 
pouring gate should run from the top of the mold down to the bot¬ 
tom of the wax collar to insure the metal filling the mold and to 
allow the good steel to reach the weld instead of being crowded out 
by the slag. The riser should be immediately above the wax collar, 
if possible, so that the slag and surplus metal can rise freely from 
the metal of the weld, and the heating gate should run from one side 
of the mold into the bottom of the collar in order that the wax can 
all run out of the mold when melted by the pre-heating torch. As 
soon as the mold is completed, the torch is applied and the wax 
melted out. The flame is allowed to play into the mold until it is 
entirely dry and then the heating gate must be plugged with clay 
to stop it up entirely. Fig. 37 shows a typical thermit weld, with 
pouring gate and riser still attached. 

Thermit Required for Given Weld. The amount of thermit 
required to make a given weld will be twice the amount necessary 
to fill the space formed by the wax collar, because one-half of the 
weight of the original powder will rise in the form of aluminum slag, 


155 



58 


AUTOMOBILE WELDING 


as already stated. On the other hand, the cubical area of riser and 
gate must be twice as great as the collar because the volume of the 
slag will be two-thirds of the total volume of the casting. It has 
been determined by experience that the weight of thermit necessary 
for a given job will be 32 times the weight of the wax required to 
form the collar for the mold; so the wax should be weighed after 
melting out of the mold in order to know how much thermit is 
required for the job. The size and shape of the mold and riser and 
gate will vary somewhat for different jobs and the relation between 



Fig. 37. Typical Thermit Weld Showing Riser and 
Pouring Gate Casting Still Attached 
Courtesy of Goldschmidt Thermit Company, 

New York City 

weight of wax and mixture will vary accordingly, but the ratio of 
32 to 1 is a good average. It is necessary to pre-heat the article at 
the joint until it is red-hot before starting to pour the metal, and 
this is done with the gasoline torch through the heating gate at the 
bottom of the mold before plugging it. 

Addition of Other Materials. When more than 10 pounds of 
thermit are required for the weld, it is necessary to moderate the 
heat of the reaction slightly, and this is done by adding small pieces ® 
of clean steel to the powder. These may be punchings, rivets, or 
any other soft steel pieces but must be free from grease to keep 









AUTOMOBILE WELDING 


59 



carbon out of the mixture, and from 10 to 15 per cent of the weight 
of the thermit may be added in this way. About 2 per cent of pure 
metallic manganese should also be added in order to increase the 
strength of the weld. If the manganese is not obtainable, 3 per 
cent of ferromanganese may be added instead, although it increases 
the violence of the reaction and hardens the metal. 

Applications of Thermit Welding. The applications of thermit 
welding are numerous, although the process is better suited to large 


Fig. 38. Broken Stern Post of Boat Welded by Thermit Process 
Courtesy of Goldschmidt Thermit Company, New York City 

jobs where the saving in cost of new pieces will justify the cost of 
the work. It will be evident also that the process lends itself better 
to welding large articles than small ones and experience up to the 
present shows that most thermit welding has been done on such 
large articles as engine and machine tool frames, locomotive side 
frames, and motor cases. Another application is the repair of stern 
and rudder posts of vessels, Fig. 38. The widest application seems 
to be in steam railroad shops and, while it is true that the electric 


157 




60 


AUTOMOBILE WELDING 


arc-welding process is rapidly superseding all others for that service, 
some of the work done is worthy of description. Considerable saving 
has been made by doing the work without dismantling the engines in 
order to get at the break. The process is to form the mold about 
the break, as described, and set the crucible above it ready for 
pouring. Where it is possible to lay the article on the floor, as when 
welding crank shafts or a broken link, the job is much easier and 
quicker to perform. 

If the brake is in the upper part of a locomotive frame, for 
example, the break should be cut out about an inch and the frame 
jacked apart another quarter of an inch. The inch space is for 
filling and the \ inch is to allow for shrinkage; so the jacks should 
be removed as soon as the mold is filled. Breaks in other parts of 
locomotive frames are treated in the same way. For welding driv¬ 
ing-wheel spokes, it is best to heat the adjacent spokes with a torch 
to expand them before welding the broken ones, and then allow them 
all to cool at once. Rail welding for street railways is another 
application of thermit. In all cases it is necessary to clean the 
metal thoroughly around the joint to remove grease and scale, and 
this is best done with a sand blast so as to insure bright clean 
metal to fill against. For work of this nature it pays to provide 
the fullest equipment in order that there may be no failures, because 
it is a very expensive operation and very hard to do over again. 


158 




































A FIFTEEN-YEAR-OLD APPERSON CAR 

Built in 1901, and, when built, was considered quite a fine automobile. It was equipped 
with a 10-horsepower, double-opposed motor, and was driven by a single chain; the wheel¬ 
base was only 78 inches. This was one of the first cars built with a left-hand drive; it 
was equipped with full-elliptic springs front and rear, and patent leather fenders. 




APPERSON EIGHT-CYLINDER CAR WITH FOUR PASSENGER “CHUMMY” 

ROADSTER BODY 

Courtesy of Apperson Brothers Automobile Company, Kokomo, Indiana 


■ 1 


160 










GASOLINE AUTOMOBILES 

PART I 


INTRODUCTORY 

Of all the applications of the internal-combustion motor, it is 
safe to say that none is more important than that applied to the 
propulsion of the modern motor vehicle—the automobile—which 
nowadays throngs the roads and streets of all civilization and serves 
a myriad of utilities as they never have been, and never could be 
served, by animal transportation. 

Standardized, inexpensive to buy, and inexpensive to operate, 
almost unfailingly reliable, and proved capable of use in the hands 
of even the most unmechanical of operators, the automobile is at 
last coming fully into its own—its design becoming recognized as a 
branch of engineering by itself, its manufacture constituting one of 
the greatest of the mechanical industries, and its use being a common 
necessity. 

Naturally, in so tremendous a development, there is sustained 
by the general public every possible sort of relationship with the 
new conveyance, from that of the merely casual observer or occa¬ 
sional user to the more interested owner; and thence on, in ever closer 
and closer touch with the full significances of this field of engineering, 
to the high-skilled and well-paid drivers of cars, the experts who 
repair them, the shopmen who build them, and the engineers and 
draftsmen who design them. 

All along this line there is a crying need for knowledge—a 
demand for definite, specific, usable information concerning the 
science upon which the motor vehicle is based, and the practice upon 
which its construction and performance are founded. 

With regard to no other field of engineering of similar impor¬ 
tance—in which there is invested anything like a similar amount of 
capital, or in which there are anywhere near as many people inter¬ 
ested—is there such a lack of correct and authoritative literature as 
in the automobile field. 



2 


GASOLINE AUTOMOBILES 


This undoubtedly is due to two conditions that have been 
involved in the rapid growth of the automobile from a mere experi¬ 
ment to an achieved and commercial fact. The first condition is 
the circumstance that the men who have most studied the auto¬ 
mobile from an engineering standpoint, and who are best informed 
about it, have not had the time to place upon paper the facts with 
which they are acquainted. The second condition—resulting from 
automobile design and engineering practice having developed so 
rapidly—has been the lack of time for the establishment of a formu¬ 
lated science, founded upon tabulated knowledge, upon which to base j 
textbooks of a genuine and permanent authority. 

It is these conditions, prevailing until within a very recent 
period, that render it reasonable to assert that the present course is ! 
absolutely the first printed matter in which text and illustrations j 
are not only up to the minute in accuracy and completeness, but in 
which there is embodied the further certainty of substantially meet- ' 
ing the needs of students of this subject for some time to come. 

In what follows, for example, will be found advanced and com¬ 
prehensive treatment of the very latest devices that are applied in 
automobile engineering, all carefully described and their essentials 1 
fully analyzed, and with their important details fully illustrated. 

PAST AND PROSPECTIVE DEVELOPMENT 

First Automobile. Credit for the first conception of the auto¬ 
mobile has been variously given to many men and to many 
countries. 

Dismissing, as without proper place in a work of this character— 
however interesting these may be from other standpoints—the various 
wholly or semi-mythical accounts that have come down from past 
ages and ancient civilizations concerning self-propelled vehicles,, 
the real fact seems to be that the modern automobile was almost 
simultaneously conceived in both Europe and America. 

Thus in France there was the work of the inventor Cugnot, who 
in 1804 sought to provide Napoleon’s armies with steam-driven 
tractors for towing gun carriages, and who built and operated a first 
model, with some success—on good highways. 

In the United States, practically contemporaneous with the 
foregoing, was the curious amphibious vehicle of Oliver Evans, which 



GASOLINE AUTOMOBILES 


3 


is declared to have moved by its own power, not only in the water, 
but on the streets of Philadelphia, in 1787. 

Early Attention to Steam Commercial Vehicle. A curious phase 
of the early days was that the greatest progress was made with steam 
busses, traction engines, and similar vehicles of utility. Despite 
their various good points, as viewed from their day and age, each and 
every one was to some extent a failure. As we look back on this, it 
was not so much because of inherent defects in the mechanism as it 
was from a lack of roads suitable for speed. 

Influence of the Bicycle. Following these early attempts, the 
bicycle had been introduced, but, with solid or semi-solid tires, it 
was clumsy and heavy and made only moderate progress. A sudden 
impetus came with the advent of the pneumatic tire. Almost within 
weeks after their first exploitation, pneumatic tires were practically 
tested. The bicycle advanced from the toy to a recognized necessity. 
Rendered simple by its very limitations—its size determined by the 
size of the average man, its weight determined by the weight 
of the average man, and its speed a function of the muscular energy 
of the average man—the bicycle required only a few years to evolve 
it to seemingly almost final standardization, as well as to degrees of 
mechanical perfection and manufacturing economy that the wildest 
enthusiast had hardly dared to hope for a few years earlier. 

In the meantime, certain matters had been made evident. The 
bicycle, with its pneumatic tires, having shown how to secure a 
maximum effect from a minimum of power the utmost of efficiency 
and speed with the least energy—it was a most obvious sequence 
to turn again from muscular power to mechanical energy for means 
of propulsion. 

Pioneers. Among the first, and by many considered the great¬ 
est, of the real pioneers of modern automobiles, the name of Gottlieb 
Daimler must forever rank high. 

Commencing with a motor bicycle, Daimler was undoubtedly 
the first man to realize, in any especial degree, the possibilities of 
gasoline-engine design as applied to high-power and light-weight 
construction. And as founder of the great Daimler Company, in 
whose famous Mercedes automobiles there were first applied the 
float-feed carbureter, the long-stroke motor, the pressed-steel frame, 
annular ball bearings, the honeycomb radiator, and a host of minor 






4 


GASOLINE AUTOMOBILES 


improvements that subsequent general adoption proved of basic 
importance, Daimler's claim to the most that his admirers have 
asserted for him is hard to dispute. 

Other important contributions to automobile engineering were 
wheel steering and the sliding gear, first applied by Panhard and 
Levassor, of France, and electric ignition, the early development of 
which was largely in the hands of the Marquis de Dion of France. 

With first principles established and practical features of con¬ 
struction demonstrated, the age of the automobile was fully begun. 
Unfortunately for the credit of America, however, the incomparable 
superiority of European roads resulted in all of the most important 
and advanced development work being carried on abroad, so that 
the modern motor car had its evolution well under way and its type 
fully fixed long before American business men began seriously to 
regard it as a device of commercial importance. 

Early American Progress. While there is considerable difference 
of opinion as to the first cars, the fact has been established that the 
Duryea Brothers experimented as far back as 1886, began a car in 
1891, and finished it in 1892—a car which actually ran. A quartering 
rear view of this car is shown in Fig. 1. This vehicle had wheels of 
the buggy type, and a single-cylinder engine which drove a variable- 
speed friction device, the rear wheels being turned by means of a 
double-chain final drive. A single lever moved up and down to 
control the speeds, and to right or left for steering, the speed control 
being accomplished through a connection to the governor mounted 
on the lever. A spray mixer for the fuel, and electric ignition were 
used. It was materially improved in 1893, and again in 1894 and 
1895. One of the third types built was the winner of the famous 
Times-Herald race, held in Chicago on Thanksgiving Day, Novem¬ 
ber, 1895, for a distance of 52 miles, and which really marked the 
start of the automobile industry in this country. 

J. W. Lambert built a three-wheeled car in 1892, which was 
described in the first issue of the first automobile journal to be 
published in the English language, The Horseless Age, November, 
1895. The next year, 1893, Elwood Haynes and the Apperson 
Brothers, Edgar and Elmer, started work on the Haynes-Apperson 
car, Fig. 2, which was finished in 1894, and made its initial trip on 
July 4, 1894. In 1893, also, A. J. Pierce, Sterling, Illinois, had 


164 



GASOLINE AUTOMOBILES 


5 



produced a car which would run, in fact was a competitor in the 
Times-Herald race, as was also that of Max Hertel, whose later 
productions were brought out by the Oakman Motor Vehicle Com¬ 
pany, Greenfield, Massachusetts. Henry Ford is said to have 
worked on a car in 1893, although his first period of real activity 
dates from 1902 and 1903. R. E. Olds, then a manufacturer of sta- 


Fig. 1. Duryea Brothers 1891-1892 Vehicle—American Prototype of Modern 
, Gasoline Automobile 

Courtesy of Charles E. Duryea 

tionary gas engines, is said to have made experiments with a car in 
1886, although little or no progress was made until ten years later, 
the first Oldsmobile having been brought out in 1899. 

George E. Whitney should be given credit for a great deal of 
the early work in steam-propelled machines, his work really having 
inspired the Stanleys, as well as the early constructors of the Loco¬ 
mobile, Mobile, and others. A St. Louis man, named Lewis, pro- 













6 


GASOLINE AUTOMOBILES 



duced an electric car in that city in 1893/and it is said that the 
newspapers of April of that year mention its appearance on the 
streets, where it created a sensation. 

In 1895, and from then to 1897, the following pioneer cars are 
known to have been produced, some of them claiming an earlier date 
than they are generally credited with: Altham, St. Louis, Loomis, 
Morris and Salom electric (95), Booth-Couch, Pope (Columbia) electric 
(96-97), McIntyre electric (96), Stearns one-cylinder gasoline (96), 


Fig. 2. First Haynes Automobile, Built in 1893 and Equipped with a 
One-Horsepower Engine 

Courtesy of Haynes Automobile Company, Kokomo, Indiana 

Woods electric (96), Baldwin first American commercial car (96), 
Searchmont, Mobile, Stanley steamer, Pope (Columbia) two-cylin¬ 
der gasoline (96-97), Winton (96-97), Riker electric (97), Orient (97), 
Crestmobile three wheeled one-cylinder (97), Barrows electric 
(97-98), and a number of others. 

Alexander Winton, president of the company bearing his name, 
had so far perfected his car in 1897 that early in 1898 he began to 
sell them commercially, delivering a total of 21 machines that year. 










GASOLINE AUTOMOBILES 


7 



The first went to Robert Allison, Port Carbon, Pennsylvania, on 
April 1st, and the twelfth to J. W. Packard, of Warren, Ohio, who 
started a factory there the following year for the production of a 
similar machine. Fig. 3 shows the first Packard, dated 1899, and, for 
comparison, the 1915 product of the present Packard Company. 
In 1896, Louis S. Clark started work on a small two-cylinder gaso- 


Fig. 3. The First Packard, Built in 1899, Compared with the 1916 Car of the Same Make, 
Indicating 17 Years of Progress 

line-engine car, but this was a failure. However, he succeeded one 
j year later with a single-cylinder air-cooled machine, and in 1898, 

| with a two-cylinder water-cooled type, which was incorporated in the 
Autocar commercial car shown in Fig. 4. This was probably not 
preceded by any commercial car other than Baldwin s crude effort 
of 1896, and is the predecessor of the present Autocar line of com¬ 
mercial cars. All the early machines, with the exception of this one, 


167 












8 


GASOLINE AUTOMOBILES 


were pleasure types, but some ten years later this company abandoned 
them and now builds commercial cars exclusively. 

The Haynes-Apperson product progressed very rapidly, follow¬ 
ing the awarding of the Times-Herald prize for the best balanced 
engine, although beaten in the contest for speed by several others. 
This was a two-cylinder opposed motor, and this firm, with the 
Appersons as the mechanical geniuses and Haynes as the financial 
man, should be given due credit for this engine, which influenced 



Fig. 4. First Commercial Car Built by the Autocar Company in 1898. Probably 
the Second Commercial Automobile Built in America 


practically all the experimenters of that day to work upon the two- 
cylinder type. Beginning in 1895 and for the next three or four 
years, the improved Haynes-Apperson product was prominent in 
racing, as were also Winton, Riker, the Duryeas—Kenneth Skinner, 
of Boston, importing the De Dion-Bouton (French) product from 
1893 to 1896 and others. A 1900 Haynes-Apperson is shown, Fig. 5. 

In 1897, the Duryeas split, J. Frank going to Springfield, 
Massachusetts, where he identified himself with the present Stevens- 


168 




GASOLINE AUTOMOBILES 


9 


Duryea Company, while Charles E. remained in Reading, Pennsyl¬ 
vania, removing recently to Saginaw, Michigan. 

In 1898, Elmer Apperson drove a car from Kokomo, Indiana, 
to New York City to deliver it to a customer, this representing the 
longest continuous run made up to that time. The following year, 
Winton emulated this by driving from Cleveland, Ohio, to New 
York City, this, however, being with a one-cylinder motor, as Winton 
did not produce his two-cylinder opposed engine until 1900, and 
in a commercial way, until 1901. 



Fig. 5. The Haynes Two-Cylinder Opposed Vehicle of 
1900. Haynes and the Appersons Were among the 
Country’s Pioneers, Constructing a Car in 1893 


In 1898, also, the industry had progressed to the point where 
there were four electric cars (Pope, Riker, Barrows, and Waverley) 
shown at the Electrical Exhibit held in Madison Square Garden, 
New York City. 

In the same year the Morris and Salom interests were transferred 
to the Electric Vehicle Company, Hartford, Connecticut, which 
later acquired the Riker Electric Motor Company, Brooklyn, New 
York, and still later the Pope (Columbia) interests in Hartford. 
At the latter time, the name Columbia was applied to its whole 
product. Riker continued with this concern as chief engineer until 
1899, when he severed his connection and joined the new Locomobile 


169 






10 


GASOLINE AUTOMOBILES 


Company of America as chief engineer, a position he holds to this ‘ 
day. 

As has been stated, the first Stearns work was started in 1896, 
and the single-cylinder car was completed in 1897. This was refined 
in 1898 and 1899, a two-cylinder being turned out in the latter year, 1 
in addition. This was not placed on the market for two years, but “ 
contained a number of very advanced features, such as left-hand 
steering, wire wheels with pneumatic tires, sliding-gear trans- J 
mission, etc. 

The first Waverley electric was turned out in January, 1897, .'j 
for Charles F. Smith, this being a stanhope design with 36-inch ] 
wheels, single-tube tires, herringbone gears, 3J-horsepower motor, I 
and Porter battery. In 1899, this firm turned out its first electric I 
delivery wagon. In 1898, the McIntyre Company produced its first | 
gasoline car, with a single-cylinder, water-cooled motor, and trans- I 
mission by means of belt with tight and loose pulleys. The first 1 
Baker electric was brought out in 1899, this being of the piano-box 1 
type. That same year, the first Knox, a three-wheeled affair with a 
single-cylinder air-cooled horizontal motor, was turned out from the I 
Springfield, Massachusetts, factory. In 1898, E. R. Thomas visited j 
the De Dion factory and the following year constructed his motor 
tricycle with a De Dion type of motor. This was the forerunner of 
the Thomas machines, the first of which was produced in 1901. 

The year 1901 was a big one in early car development. For one • 
thing, the Pan-American Exposition at Buffalo, New York, had a 
section for the display of the early cars, as well as a track upon which 
to try them. In addition, this was preceded by the first endurance 
contest from New York to Buffalo, which was as big a factor at that ! 
time as the earlier Times-Herald race had been. One result of this, 
for instance, was the production of the first American shaft-driven 
car, the last of that year, by Louis S. Clark. In this year, too, the 
Oldsmobile factory began to turn out cars in quantity, some 425 
being produced despite a destructive fire. 

Howard E. Coffin, while a student at the University of Michigan, 
had produced a steam car in 1898. Later, he joined the Olds Com¬ 
pany, and still later was prominent in the formation of the present 
Hudson Company, of which he is vice-president and chief engineer. 

In that year (1901), the Olds Company bought its motors from the 


170 





GASOLINE AUTOMOBILES 


11 


Leland and Faulconer Company, its transmissions from Dodge Broth¬ 
ers, and its upholstery and body work from Barney Everitt. Every 
one of these firms has been prominent in the industry since, the first- 
named forming the basis for the formation, in 1902, of the present 
Cadillac Company, the second-named having been responsible for 
the important parts in the Ford car up to 1912, and a large part of 
them in 1913 and 1914, severing their manufacturing connections 
in the last-named year to bring out a low-priced car of their own. 

Everitt, with others, formed the Wayne Auto Company in 1903, 
this developing later into the E. M. F. Company, in which he was 
the “E” part, this, in turn, being taken over later by the Studebaker 



Fig. 6. First Four-Cylinder Ford Car Produced in 1905, the Predecessor of the Sturdy 
Little $400 Car of Today 


Company. About 1901, J. D. Maxwell, who had been with the Olds 
Company, interested W. T. Barbour and G. B.- Gunderson of the 
Detroit Stove Works, and W. E. Metzger of Detroit, in the formation 
of the Northern Automobile Company. The machine produced was 
like the Oldsmobile but with more power and a higher price. From 
this concern, which failed later after several reorganizations, Max¬ 
well withdrew, and in 1903, with Benjamin Briscoe, who had been 
prominent in parts-manufacture in Detroit, notably radiators and 
fenders, formed the Maxwell-Briscoe Company, of Tarrytown, 
New York, this later forming the nucleus of the United States 
Motor Company, which in turn was succeeded by the Maxwell 


171 





12 


GASOLINE AUTOMOBILES 


Motor Company. Out of this pioneer firm also, W. E. Metzger 
came to the E. M. F. Company, previously mentioned, he forming 
the “M” part, the firm actually being the Everitt-Metzger-Flanders 
Company. 

Early in 1901, the Vehicle Equipment Company of New York 
City started with a factory in Long Island City. This was later 
called the General Vehicle Company, and is still in existence, using 
the same factory. It is claimed that this plant has not been closed 
for a single working day, since started in 1901, a great record, for 
the early trials and tribulations were great. Haynes and the Apper- 
sons separated in November, 1901, forming two separate companies, 
each of which is still doing business. 

In 1902, Ford had developed and was producing, in a small 
way, a two-cylinder machine which in outward appearance was 
similar to the one-cylinder Cadillac. In June, 1903, he had inter¬ 
ested capital and the company was formed with a capitalization of 
$100,000, starting with but $28,000 in actual cash. From this small 
beginning has grown the present tremendous organization, which 
builds 300,000 cars a year, equal to, approximately, 1000 a working 
day. In 1912, this firm had a turnover of more than $80,000,000 and, 
in 1913, this approximated $100,000,000. An example of their 1905 
product is shown in Fig. 6. It was also from the Ford Company 
that W. E. Flanders, the presiding genius of the E. M. F. Company 
came, later heading the Everitt Company, and still later the immense 
Maxwell Motor Company. 

Through his interest in the work of Skinner in New England 
and in his imported De Dion product, George N. Pierce, then a 
manufacturer of bicycles in Buffalo, New York, started building the 
Pierce motorette in 1901. This was a machine propelled by a 21- 
horsepower De Dion motor placed on the back axle. The fact that 
one of the first of these completed the New York-Buffalo run of that 
year and that some of these are still running (1915) shows that good 
workmanship and material were put into them. This was the begin¬ 
ning of the present Pierce-Arrow Motor Car Company. 

From this point (1901) on, it was simply a case of improve, 
develop, prove out, put on the market, and start over again. The 
single- and two-cylinder machines of that day, with short wheelbases 
and many crudities, slowly gave way to the four-cylinder form with 


372 



GASOLINE AUTOMOBILES 13 

comparatively long wheelbases, Fig. 7, and with much of the rough¬ 
ness taken out. These, in turn, have been largely replaced in the 
bigger machines by six- and even eight-cylinder motors, while the 
wheelbases continue to grow longer and longer each year. In the 
matter of refinements, such a point has now been reached that people 
think perfection has been attained, and that no further refinements 
or improvements can be made. Yet such is as far from the actual 
case now as it was ten years ago, in the opinion of far-sighted experts. 
Increased efficiencies of the motor are expected, notably along the 


Fig. 7. The 1904 Stevens-Duryea, First Car to Incorporate the Unit Power Plant, Multiple- 
Disk Dry Plate Clutch, and Semi-Floating Axle 

various slide- and sleeve-valve forms; the use of electricity and air 
offers many attractive advantages, some of which may be worked 
into car improvements and refinements; many advantages are claimed 
for the hydraulic transmission; there is room for much body work of 
real merit; the puncture-proof tire offers a wonderful field for inven¬ 
tors and experimenters; there is still something to be said of car 
suspensions; improvements are being made every day in carburetion, 
lubrication, ignition—in short, who can say that any feature of the 
car today, despite its perfection, will be present in the car of ten 
years from now? 


173 






14 


GASOLINE AUTOMOBILES 



174 































































































































GASOLINE AUTOMOBILES 


15 


FEATURES OF MOTOR=CAR CONSTRUCTION 

GENERAL OUTLINE 

In general, all motor cars follow along the same broad lines. So 
much has this become the case in the last few years that a large 
number of the parts, units, and accessories entering into the con¬ 
struction of the car have become standardized and may, to a certain 
extent, be taken off one car and placed on another without exten¬ 
sive alteration. This has been done, too, without interfering in any 
way with the initiative of the various designers. 

Groups and Parts. Practically all modern gasoline motor cars 
may be divided, in a mechanical sense, into six groups of parts or 
units. These are: (1) The engine or power producing group; 
(2) the clutch group, needed, as will be explained later on, with all 
forms of explosion motor; (3) the transmission, or gearset, for pro¬ 
ducing the various car speeds and different powers, while the engine 
gives a practically constant speed and power output; (4) the final 
drive group, which connects the speed variator or transmission with 
the rear wheels, and thus propels the car. Of a necessity, this includes 
the rear axle, while the front axle is usually grouped with the rear; 

(5) the steering device, for controlling the direction of motion; and 

(6) the frame, upon which all these and their various accessories 
are hung, with the springs for suspending the frame upon the axles 
of the car. There is, of course, a seventh group, the body, but that 
need not be discussed here, since reference is now had only to the 
mechanical parts. 

Engine Group. In the large diagram of a modern motorcar, 
Fig. 8, the sectional side view is shown above and the plan view 
below. In this, note that the engine is placed at the front of the 
outfit. This is now the general position, practically all modern 
motorcar manufacturers using it. A few cars have the motor located 
on the rear axle to save the parts necessary for connecting the two, 
while formerly the middle position was a favorite one. The purpose 
of the engine is to generate the power. This is done by the drawing 
in, compressing, and exploding of gas produced from gasoline. 

Carburetion Subgroup. The production of the gas necessitates 
what is called a carbureter; carrying the liquid gasoline necessitates 
a good-sized fuel tank , piping is needed to connect the two; the fuel 


16 


GASOLINE AUTOMOBILES 


is not always pure and must be filtered, necessitating a strainer; 
means for turning on and off the supply of liquid must be provided in 
the form of a cock, while the gas produced is taken into the engine 
through an inlet manifold. These and other parts, the functions and 
construction of which will be explained in full later on, constitute 
the carburetion subgroup. 

Inlet and Exhaust Valves. In order to get the gas, which is 
produced by the carburetion group, into the motor cylinders at the 
proper time and in the proper quantity, there are needed inlet valves, 
and, for their operation, cams, which are placed on a camshaft, which, 
as will be explained in detail, is driven from the crankshaft of the 
engine. In addition, after the gas has been admitted into the cylin¬ 
ders, compressed, and exploded, thus producing its power, it is of no 
further use and must be removed from the cylinders. As this must 
be done at the proper time, and as the proper quantity must be 
removed, additional valves known as the exhaust valves are needed, 
these also being operated by cams on a camshaft, driven from the 
crankshaft. 

Exhausting System. Further, in passing out, the exhaust gases 
pass through a particular pipe, known as the exhaust manifold, and 
thence to the back of the car. As there remains considerable pressure 
in these gases, when allowed to escape freely, they make much noise 
and considerable smoke, so that all cars are required by law to carry 
and use a muffler. The name explains the purpose of this—it 
muffles the noise. The exhaust gases pass through this and thence 
out into the atmosphere. This whole group of parts might be called 
the exhausting system, for the purpose of removing the gases after 
use, as contrasted with the carburetion system, for producing and 
supplying the gases. 

Ignition System. In an intermediate stage comes the explosion. 
This is done by means of an electric spark, which is produced within 
the cylinders by means of a spark plug. The electric current which 
is the original source of this spark may be produced by means of a 
form of rotary current producer, known as a magneto, or it may be 
taken from a battery. In any case, such current must be brought up 
to a proper strength and the various sparks must be produced at the 
exact time they are needed. All this calls for auxiliary apparatus. 
Moreover, the current producer, if it be a magneto, must be driven 




GASOLINE AUTOMOBILES 


17 


from some rotating shaft; there must be a suitable place provided on 
the engine for it, with means for holding it there, as well as for quick 
and easy removal. All this, as a complete unit, is called the ignition 
system. 

Cooling System. In the production of the gas for use, and in its 
explosion and subsequent expanding and exhausting, a great amount 
of heat is created. Some idea of this may be gained from the two 
simple statements that the explosion temperature often runs up as 
high as 3000° F., and the exhaust temperature frequently is as high as 
1500° F. In order to take away this heat, which communicates itself 
to the walls and parts of the engine wherever it contacts with them, 
and by conduction, to other parts with which it does not contact, 
the parts which are exposed to the greatest heat are surrounded by 
hollow passages, called jackets, through which water is forced or 
allowed to flow. This might be called a collector of the heat, for it 
is then conducted to the radiator, a device for cooling the water, 
which is there cooled off and then used again. In order to circulate 
the water, a pump is used, driven from some rotating shaft, supported, 
removable, accessible, etc. All this, with the necessary piping to 
connect the various parts, is called the cooling system. 

Lubrication System. Moreover, as the various parts rotate 
within one another, bearings , or parts specially designed to facilitate 
easy and efficient rotation, must be used. Furthermore, in and on 
all such bearings a form of lubricant is necessary, as it is also between 
all sliding parts. In order to have a copious supply at certain points, 
various forms of lubricators or oil pumps are needed to circulate it; 
pipes must be provided to carry it; a sight feed, or visible indication 
that the system is working, must be placed in sight of the driver 
(usually on the dashboard); an oil tank for carrying the supply must 
be provided; and a location found for the lubricator or pump and 
means for driving, removing, adjusting, and cleaning it. • All this as a 
whole comes under the head of the lubrication system. This system 
covers in addition isolated points requiring lubrication, and the 
different ways used to supply them. 

Starting System. In order to start the engine, a starting handle 
is provided on all older cars, with possibly a primer working on the 
carbureter, and other parts. On modern cars, this work of starting 
is done by electricity, which requires a starting motor, a battery, a 


177 


18 


GASOLINE AUTOMOBILES 


switch for connecting the two, wiring, buttons, and other parts. 
All this combined is called the starting system. 

Flywheel. At one end of the engine shaft, there is provided 
the flywheel. This is a large, wide-faced member of metal, com¬ 
paratively heavy, the function of which is to store energy (by means 
of rotation) as the engine produces it, and to give it back to the engine 
at other parts of the cycle when energy is needed and none is being 
produced. In short, it is a storehouse of energy, absorbing the same 
from the engine, and giving back the excess when it is needed. In 
general, this effect is greatest when the mass of metal is farthest from 
the center, consequently flywheels are made of as large a diameter 
as is possible considering the frame members. Note this in the 
illustration, Fig. 8. 

Clutch Group. Within the flywheel the clutch is located, 
generally. This is a device, by means of which a positive connection 
can be made with the engine, or disconnection from it effected at the 
driver’s will. A moment’s consideration will show that when such 
disconnection is made with the engine running, it will continue to run 
idly, and will not drive the car, which, perforce, must stand still. 
Similarly, when the positive connection is made the motor will drive 
the clutch and such parts beyond it as are connected-up at the time. 
This arrangement is necessary because of a peculiarity of the gas or 
gasoline engine—it cannot start with a load but must be started and 
allowed to get up speed before any load is thrown upon it. This is 
the function of the clutch, for at all starting times it is thrown out, 
disconnecting the balance of the driving system from the engine, so 
that the latter may speed up. When this has been done, the proper 
gear is engaged, and the clutch is thrown in so that the engine picks 
up this load. 

Like other parts, this must have a means of connecting and 
disconnecting, a proper place, proper fastenings, means for adjust¬ 
ment and removal, other means for lubrication, as well as other parts. 
All this, collectively, is called the clutch group. 

Transmission Group. As has just been pointed out, the engine 
cannot start with a load; it must get up speed first. Furthermore, it 
must be started under a light load. This necessitates certain gearing, 
so that, when starting, the power of the engine may be multiplied 
many times before reaching the wheels, and, therefore, before it is 


178 



GASOLINE AUTOMOBILES 


19 


applied to the propulsion of the car. Furthermore, it has been found 
convenient to have a series of such reductions or multiplications. 
These correspond to the various speeds of the car, for obviously, if 
the power is multiplied by means of gearing, it is reduced in speed in 
the same ratio. This whole group of gearing is the transmission or 
gear set, and the various reductions are the low speed, intermediate, 
and high in a three-speed gearbox; and low, intermediate, second, and 
high in a four-speed gearbox. A gearbox is always spoken of by its 
number of forward speeds, but there is in all of them, in addition to 
the forward speeds, a reverse speed for backing the car. 

In the usual form, these gears are moved or shifted into and out 
of mesh with one another, according to the driver’s needs. For this 
purpose, shifting gears must be provided within the gearbox, that is, 
the arrangement must be such that the proper gears can be moved 
back and forth, with a shifting lever outside for the driver’s use, and 
proper and accurate connections between the two. The gears must 
be mounted on shafts, these in turn on bearings, the bearings must 
be supported in the gear case, and this must be supported on the frame. 
In addition, there must be suitable provision in the gear case cover 
for inspection, adjustments, and repairs; all the moving parts must 
be lubricated; all parts must be protected from the dust, dirt, and 
moisture of the road, etc. All this comprises the transmission or 
gearing group, which properly ranks second to the engine group in 
importance. That is, next to producing the power quickly, efficiently, 
and cheaply, it is important to use it with equal quickness, efficiency, 
and cheapness. 

Final Drive Group. Driving Shaft. The connection from the 
transmission to the rear axle in pleasure cars is usually by shaft, 
called the driving shaft. On the majority of motor trucks, however, 
it is by means of double side chains, which will not be discussed here. 
This shaft is generally inclosed in a hollow torque tube, with suitable 
connection at the front end to a frame cross member, and at the rear 
to the axle housing. Its construction is generally such that it contains 
a bearing for the driving shaft at both front and rear ends. In addi¬ 
tion, the majority of final drives contain at least one universal joint, 
and many of them contain two. As its name indicates, this will work 
universally, that is at any angle, its particular function in the driving 
shaft of an automobile being to transmit power from a horizontal 


179 


20 


GASOLINE AUTOMOBILES 


shaft that of the engine clutch and transmission—to an inclined 
one—the driving shaft—with as little loss as is possible. 

Rear Axle and Differential. The driving shaft drives the rear 
axle through some form of gear, either bevel, worm, or other variety, 
and is usually a two-part shaft. The reason for cutting the rear axle, 
is that each wheel must be driven separately in rounding a curve, for 
one travels a greater distance than the other. This seemingly com¬ 
plicated act is produced by a simple set of gearing called the differen¬ 
tial, which is located within the driven gear in the rear axle. Each 
half of this is fixed to one part of the axle shaft. All these gears and 
shafts must have bearings, lubrication, means for adjustment, etc. 
On the outer ends of the axle shafts are mounted the rear wheels, 
which carry some form of tires to make riding more easy. The 
brakes are generally in a hollow drum attached to the wheels. All 
this goes to make up the driving system. 

Steering Group. The front wheels perform a different function. 
These are so hung on the steering pivots, that they can be turned as 
desired to the right or the left; in order to have the wheels work 
together, a rod, called the cross-connecting rod, joins them; while the 
motion is imparted to them by means of another rod, called the 
steering link, which joins the steering lever or arm with the right-hand 
(or left-hand as the case may be) steering pivot. The last-named lever 
projects downward for this purpose from the steering-gear case, being 
itself moved forward and back by the rotation of the steering wheel 
in the driver’s hands. 

The transformation of the rotation or turning motion of the hand 
wheel into a pushing (or pulling) or longitudinal movement is accom¬ 
plished within the steering-gear case by means of a worm and gear; 
a worm and partial gear; or, in some cases, a pair of bevel gears. All 
these parts need more or less adjustment, lubrication, fastening means, 
etc., the complete group being designated as the steering group. 

In addition, the steering wheel and post carry the spark and 
throttle levers, with the rods, etc., for connecting them to the igniting 
apparatus (magneto, timer, etc.), and the carbureter, respectively. 
The purpose of the spark lever is to allow the driver to vary the power 
and speed of his engine by an earlier or later spark, according to his 
driving needs. Similarly, the throttle lever is for the purpose of 
opening or closing the throttle in the intake manifold of the carbu- 


180 


GASOLINE AUTOMOBILES 


21 


retion system, allowing in this way more or less gas to pass to the 
engine, and thus increase or decrease its power output or speed. 
Actually, these are parts of the ignition and carburetion systems, 
respectively, but they are usually grouped with the steering, because 
located on the steering wheel and post. 

Frame Group. Little need be said about the frame. The side 
members generally carry at their front and rear ends the springs, 
which are connected to the axles, and thus support the car. The 
front cross member usually supports the radiator, and sometimes the 
front end of the engine, too. The rear cross member usually supports 
the gasoline tank, when a rear tank is used. The other cross members 
may support engine, transmission, shifting levers, or other parts 
according to their location. In general, the number and character 
of frame cross members are slowly changing, the modern tendency 
being toward their elimination. By narrowing the frame at the front, 
the engine can be supported directly on the side members. With the 
units grouped, the same is true of the other important units. 

Formerly, practically all motors and transmissions were sup¬ 
ported on a subframe, but it has been found that the same results can 
be obtained and this extra weight and work eliminated. Conse¬ 
quently, although the drawing, Fig. 8, shows a subframe, these are 
not as widely used as was the case formerly. 

When the shifting levers are placed on the outside, these are 
fastened to the frame; the steering gear is always attached to it; the 
headlights generally are supported from the frame; all step, fender, 
and body parts are attached to it; the under-pan for protecting the 
mechanism from road dirt is attached directly to it; the body, of 
course, is fastened to it—in fact is constructed with this idea in view— 
six bolts being used, generally; the muffler previously mentioned is 
usually hung from a rear-frame member; when electric lighting and 
starting are used, the battery is most often hung in a cradle, sup¬ 
ported by the frame, while the hood or bonnet is supported equally 
by the side members of the frame (usually covered with wood) and a 
rod running from radiator to dash. 

In Fig. 8, it will be noted that the engine group (1) and the clutch 
group (2) are together, really forming one unit. Back of this the 
transmission (3) and the rear axle or final drive group (5) form two 
separate additional units. When the transmission is united with the 


181 


22 


GASOLINE AUTOMOBILES 


motor (forming a unit power plant), or with the rear axle, one unit is 
practically eliminated. The different functions of the components 
are not changed, but the grouping previously pointed out becomes 
less apparent, for units (1), (2), and (3), or (3) and (5) become one, as 
the case may be. 


ENGINE ELEMENTS 

The principles of engine design and the methods and derails of 
engine construction are certainly, in interest and importance, second 
to none of the other factors that combine to produce the complete 
modern automobile. 

How automobile engines operate, the reasons underlying the 
various details of different designs, and the relative merits of different 
constructions are all too little understood by the generality of those 
who have to do in a practical way with the new conveyance. 

Cycles of Engine Operation, In all motors, of whatever sort, 
and of any type whatever other than those in which there is a per¬ 
fectly continuous development of the power through constantly 
rotating elements—as in the electric motor and the steam turbine— 
there must be reciprocating elements that function through indefi¬ 
nitely repeated series of operations. Such a series of operations is 
termed the cycle of the engine, as is abundantly explained elsewhere 
herein, so it will suffice here to call attention to some of the merits 
and demerits of the different cycles that are in practical use. 

Two-Cycle Engines . That type of internal-combustion engine 
in which every stroke in one direction is a power stroke affords a 
maximum of power impulses to any given number of engine revolu¬ 
tions, but because of other limitations it is not always possible to 
make a two-cycle engine run as fast as a four-cycle, so that in the 
generality of cases the number of explosions in a given period of time, 
or for a given vehicle speed, is no greater with a two-cycle than with 
a four-cycle engine. 

In addition to this, most two-cycle engines are often difficult 
to start, apt to be wasteful of fuel, not at all flexible in the matters 
of speed and pulling power, and in various other respects difficult 
to apply to automobile service. Their greatest merit is their extreme 
simplicity. 

Four-Cycle Engines . The four-cycle engine is the type by 


GASOLINE AUTOMOBILES 


23 



which nine hundred and ninety-nine out of every thousand of present- 
day automobiles are propelled. Varied through an immense number 
of possible forms, and with minor differences in the product of every 
maker, its fundamental functioning has nevertheless proved so far 
the most suitable for automobile propulsion. 

With the succession of suction, compression, explosion, and 
exhaust strokes afforded by the four-cycle motor, there is secured a 
very positive and reliable functioning, and by the expedient of a 
sufficient cylinder multiplication to afford good mechanical balance 
and frequent power impulses, its flexibility, durability, and practical 


Fig. 9. Eight-Cylinder V-Type Motor of the Latest Cadillac Car Shown Installed 
in the Chassis 

quality in every respect can be brought to very high standards in a 
well-designed and honestly built motor. 

At the same time, the fact that so much more attention has 
been paid to the four-cycle motor than to any of its possible com¬ 
petitors for popular favor undoubtedly accounts in some measure 
for its present pre-eminence, and it is an open question with many 
engineers as to just what virtues might or might not be realized 
with other constructions were they as exhaustively experimented 
with and exploited. 

Cylinder Multiplication. There seems no reasonable limit to 
the extent to which cylinder multiplication can be carried, in the 
effort to improve the mechanical balance and to even the torque of 






24 


GASOLINE AUTOMOBILES 



gasoline motors, but established practice has, nevertheless, settled 
upon four-cylinder vertical engines as those most suitable for the 
propulsion of the average automobile—this being the least number 
of vertical cylinders with which mechanical and explosion balance 
can be secured. 

The use of six cylinders, with the crank throws 120 degrees apart, 
and the explosions occurring once for every 120 degrees of crankshaft 
Jotation, affords a smoother-running motor than the four-cylinder. 

Still better than the “six” from every standpoint but that of 
cost, which has prevented its wider application to automobiles, is the 


Fig. 10. Overhead View of Stearns-Knight Eight-Cylinder Sleeve-Valve Motor 
Courtesy of F. B. Stearns Company, Cleveland, Ohio 

V-shaped, eight-cylinder motor, of the type illustrated in Fig. 9, 
which gives a good view of the unit power plant of an equally well- 
known American machine. In both of these, there is used a four- 
throw shaft, similar to the ordinary four-cylinder crankshaft— 
which is much cheaper to manufacture than a six-cylinder crank¬ 
shaft—and the two rows of cylinders, each practically constituting 
a separate four-cylinder engine, are made to work upon the common 
crankshaft at 90 degrees apart. 

The most recent tendency in car motors is toward the eight-cylin¬ 
der V-type, following the marked success of this form in aviation use. 


184 




GASOLINE AUTOMOBILES 


25 



Not only has the V-form been produced in the poppet valve 
form but also in the Knight sleeve-valve type, an example of which 
is shown in Fig. 10. Furthermore, a considerable number of twelve- 
cylinder V-type motors have been built, a good example being 
seen in Fig. 11. 

In aviation work, no form of motor has made as great progress 
as the rotating cylinder type, which has been built usually with an 
odd number of cylinders, as five, seven, or nine; or when these are 
paired with an even number, as ten, fourteen, or eighteen. As yet, 
this type has not been applied to motorcars, but, considering its 


Fig. 11. Side View of National Twelve-Cylinder V-Type Motor 
Courtesy of Motor Vehicle Company, Indianapolis, Indiana 

advantages, it would not be strange to see this done at an early date. 
These motors have a single throw crankshaft of very light weight; 
the rotation of the cylinders at a rapid rate allows of their being air¬ 
cooled and also very light in weight, eliminating all parts and weight 
in the cooling system; the large revolving mass does away with the 
need for a flywheel, while the practical elimination of reciprocating 
parts reduces vibration to a minimum. 

In the extreme, motors of the V-type have been constructed with 
sixteen cylinders, eight in each group. These have been very suc¬ 
cessful in aeroplanes and motorboats, particularly the latter. 

Cylinders. Gasoline-engine cylinders are variously made of 
cast iron, cast and forged steel, aluminum alloys, and other materials. 




26 


GASOLINE AUTOMOBILES 



For durability, and the ability to withstand high temperatures 
without warping, nothing has been found superior to cast iron, 
though the lightness of steel and aluminum alloys has commended 
them for aviation use, and in some cases for racing automobiles. 

Cast Separately. Early and still common practice in the build¬ 
ing of multicylinder gasoline motors was the casting of cylinders 
separately, it being by this policy easier to secure sound castings, 
simpler to machine and finish them, and less troublesome to dis¬ 
assemble parts of the motor without disturbing the rest. 


Fig. 12. Studebaker Six-Cylinder Motor Showing the Block Castings of the Six Cylinders 

In a number of cases, where extremely light weight was desired, 
this method was followed but the cylinders were machined all over 
and a sheet-copper water-jacket was applied in assembling. This has 
been most successful in aeroplane work, and also for motorcars, but 
when the Cadillac changed to the form shown in Fig. 10, this construc¬ 
tion lost its principal American adherent. In addition to this con¬ 
struction, there have been a number of motors built with an applied 
water-jacket of sheet metal, this being of the built-on form. These 
have shown splendid cooling abilities, but, under the twisting and 
racking of automobile frames, particularly in later years with the 
more flexible frames, have shown too much tendency toward leakage 
to become popular. 


186 









GASOLINE AUTOMOBILES 


27 


Cast Together. The great advantage of having the several 
cylinders of one motor cast together —en bloc, as the French term it—- 
is that the alignment and spacing of the different cylinders is thus 
rendered absolute and permanent, regardless of any differences in 
adjustment that may otherwise occur in assembling. 

This construction has been applied to a large proportion of the 
small and medium-sized fours, a fair proportion of the larger fours, 
and to a considerable number of sixes. One of the latter is shown in 
Fig. 12, this being the Studebaker six, which has a bore of 3§ inches 
and a stroke of 5 inches, rating at 29.6 horsepower but actually 
developing about 60. Some idea of the extent of this practice may be 
gained from the statistics for 1914, these showing that in a total of 236 



Fig. 13. Ford Engine with Cylinders, Crankcase, and Gearbox in Two Parts 
Courtesy of Ford Motor Car Company, Detroit, Michigan 


different motors 30 were cast in threes and 93 in block. As the three- 
cylinder construction is really a block modification, this gives a total 
of 123 as compared with the individual casting, 15, and the twin, 98. 

Another advantage is that the water connections, exhaust and 
intake manifolds, etc., are rendered simpler both in their form and 
the number of their points of attachment. 

In some advanced motor designs the passages for the incoming 
mixture and the exhaust gases, and in one case even the carbureter 
itself, are all incorporated in the main casting. 

Another example of simple construction. is that illustrated in 
Fig. 13, which depicts one of the latest Ford motors, in which cylin¬ 
ders, upper half of the crankcase, and the gearbox are all cast in one 


187 







28 


GASOLINE AUTOMOBILES 


piece. The lower half of the crankcase and gearbox are similarly 
constituted of another simple pressed steel unit, while a second 
casting is used for the heads of the cylinders and the water connection. 

Piston. The pistons of automobile motors have long been made 
of cast iron, with the piston pin held in bosses on the piston walls. 
For all ordinary service this construction, well carried out, serves 
every purpose, but with the development of very high-speed motors, 
with piston speeds twice and three times as high as past practice has 
sanctioned, there is a growing tendency to substitute steel for cast 
iron in this important reciprocating element. 

Particularly in aviation motors has this been the case, the pistons 
of one well-known revolving motor, for example, being machined 
to the thinnest possible sections out of a high-grade alloy steel. In 
this motor the connecting rods are hinged to the head of the piston 
instead of to the walls, which thus can be made much thinner than 
otherwise would be necessary. This practice has been followed to a 
slight extent by some automobile manufacturers. There are now a few 
stock cars of established quality provided with pressed-steel pistons. 

In cars, too, the movement toward smaller bores and higher 
efficiency has brought about the use of much lighter pistons, this 
being done by making them thinner and shorter. The latest develop¬ 
ment has been the use not only of aluminum pistons and die-forged 
aluminum alloy connecting rods, but also of aluminum cylinders 
having cast-iron sleeves driven in to form the actual cylinder surfaces. 

Cast iron for piston rings, long used to the exclusion of every-' 
thing else, is in slight degree yielding its pre-eminence for this pur¬ 
pose also. This is because it has been found, in aviation motors 
with steel cylinders, that bronze affords greater durability and 
smoother running against the steel cylinder wall, for which reason 
bronze rings—with steel or cast-iron springs, or “bull rings”, behind 
them—have been found most advantageous. Multiple rings, three or 
more in a groove, are finding favor. Their thinness necessitates the 
use of steel. 

Connecting Rods. Established practice in connecting-rod 
design is almost all in favor of the common H-section rod, usually 
with two bolts to attach the cap. In some cases four bolts are used, 
since with four bolts a flaw or crack in one is less likely to cause dam¬ 
age than is the case when only two are used. The old scheme of 


188 


GASOLINE AUTOMOBILES 


29 



hinging the cap at one side is now practically obsolete, having been 
discarded because of the fact that it made accurate adjustment of 
the bearing surfaces almost impossible. 

Tubular rods, in place of the H-section, are giving good service 
in several of the long-stroke foreign motors, and it is difficult to see 
why this form is not superior to that in common use. The question 
of cost, however, is a consideration, since it is necessary to bore the 
hole through the inside of the rod, whereas a forged rod of H-section 
requires no machining except at the end. 

The wonderful progress in welding, however, has made it possible 
to construct a tubular connecting rod at a very low expense, and, due 


Fig. 14. Connecting Rod Machined Out of One Piece of Alloy Steel, 
with Four Cap Bolts 


to its many advantages, this is finding much favor for small motors. 
The two ends are machined and a section of tubing welded to them. 

One advantage of the tubular rod, in addition to its superiority 
for withstanding the compression load to which a rod is chiefly sub¬ 
ject, is that it can be used as a pipe to convey oil from the big end 
to the piston-pin bearing. 

In Fig. 14 is illustrated an example of a very light-weight, high- 
quality, aviation-motor connecting rod, machined out of a solid 
bar of alloy steel, and provided with four bolts in the cap. 

Crankshafts. The greatest variations in automobile crank¬ 
shaft design, aside from those permitted or made necessary by differ¬ 
ences in the quality of material, are due to the conditions involved 


30 


GASOLINE AUTOMOBILES 


in the different combinations of cylinders that can be utilized. Thus 
the number of crank throws, as well as their position, varies with the 
type of motor. 

The duty of a crankshaft is of so severe a character, involving 
the practical equivalent of thousands upon thousands of heavy 
blows, that for any but very heavy, slow-running motors, the crank¬ 
shaft should be made of nothing but the finest alloy steels obtainable. 

Valve Mechanism. In the valves and valve mechanisms of 
modern gasoline engines there have been and are impending more 
interesting changes than seem in prospect in any other portion of 
the mechanism of the modern automobile. Particularly is this the 
case with reference to the present tendency to discard the poppet 
valve with its many objectionable features. 

Even where there is no tendency toward the use of a sleeve-valve 
or slide-valve form of motor, much experimenting has been done with 
increasing the number and changing the position of the valves. As an 
example of the former, many of the cars in the last Grand Prix race, 
in France, had four valves for each cylinder, two inlets and two 
exhausts. As an example of the latter, the same race showed all but 
two makes of car with the valves in the head, either vertical or 
inclined, except in one case, in which they were horizontal. 

Poppet Valves. Though the very first internal-combustion 
engines ever made were operated with slide valves, the poppet valve 
was introduced very early in the history of this art, and has reigned 
supreme in practically all types of gas and gasoline engines. 

The chief advantage of the poppet valve is its capacity for 
continuing operative at excessively high temperatures, but since the 
cooling of engines has progressed to the status of high reliability 
this advantage is of less importance than formerly. And the dis¬ 
advantages of poppet valves—the small openings that they afford, 
the noisy and hammering action they involve, their tendency to leak 
and in other ways give out, and the necessity for frequently regrinding 
them—are objections so serious that it is not to be wondered at 
that the prospect of their elimination is so widely welcomed. 

About the only recent improvements that have been made in 
poppet valves are in the quality of material used in them—the best 
valves now being those with cast-iron and nickel heads, which offer 
a maximum resistance to warping from the heat to which they are 


GASOLINE AUTOMOBILES 


31 


subjected, and with carbon-steel stems, which are superior in their 
wearing qualities. Much use has been made recently of tungsten 
as a material for valves. Steel containing this is even harder than 
nickel steel, and experiments have shown that it does not warp as 
much. In practice, the objection found to cast-iron heads was that 
the fastenings to the carbon-steel stem were not sufficiently strong 
to withstand the constant pulling and pushing to which a valve was 
subjected. As a result they separated, causing trouble. 

In the operation of poppet valves, the cams become an important 
factor. These are the parts, which, in revolving, raise the valves 



Fig. 15. Fiat Marine Motor with Encased Valve Action 
This Photograph Protected by International Copyright 


so that they open at the proper time. In addition, they are so shaped 
as to hold them open for just the right length of time, and allow 
them to close, through the medium of the valve spring pressure, at 
the proper point in the cycle. The importance of this can be seen, 
if we consider that opening the slightest fraction of a second too late 
will reduce the amount of the charge very much, and thus lessen the 
power developed by the motor. 

Enclosures. The use of casings to enclose the valve stems, 
springs, and push rods, so as to keep these elements from exposure 


191 





32 


GASOLINE AUTOMOBILES 



to dirt, while at the same time silencing in large degree the noise they 
otherwise make, is also becoming usual. 

An excellent example of this may be seen by referring back to 
Fig. 12, in which it will be noted that the whole side of the motor 
where the valve mechanism is located is covered with a long, remov¬ 
able plate, keeping in noise and lubricant, and keeping out dirt. 
Usually, however, on a six-cylinder motor the valve enclosure is made 
in two parts, one-half enclosing the mechanism of the valves in the 


Fig. 16. Carbureter Side of Moline-Knight 50-Horsepower Motor 
Courtesy of Moline Automobile Company, East Moline, Illinois 

first three cylinders, the other, those in the last three. This is, of 
course, the preferred construction on those six-cylinder engines which 
have the cylinders cast in threes, instead of in a block, as the one 
referred to. On some motors where this construction has not found 
favor, the designers have followed the plan of enclosing the individual 
valve mechanisms. While more expensive, this method is equally 
as efficient. On the other hand, it adds to the parts, and the whole 
modern tendency has been to reduce the number of parts. 


192 














GASOLINE AUTOMOBILES 


33 


A characteristic example of present methods of casing in poppet 
valves is shown in Fig. 15, which is an example of a Fiat marine 
motor, with the valve stem pit in the side of the motor covered by a 
readily removable aluminum plate. 

Sleeve Valves. This type of valve, while not at all new, has only 
within the past few years come into considerable prominence, chiefly 
as a result of the truly remarkable performances of the Knight motor, 
which is equipped with the most advanced 
examples of this type of valve. 

Contrary to past opinion, it has been 
conclusively demonstrated that sleeve 
valves do not in any perceptible degree 
increase the tendency of a motor to over¬ 
heat, nor do they wear at any very meas¬ 
urable rate. They afford, moreover, in 
the best constructions, a much higher 
thermal and mechanical efficiency than it 
is possible to secure from the average 
poppet-valve motor, this improvement 
being due to the better-shaped combus¬ 
tion chamber that can be used, and the 
greater areas of valve opening, which facil¬ 
itate the ingress and egress of the charges. 

Another advantage in favor of the 
sleeve valve is that its timing is perma¬ 
nent and unchangeable, and does not 
alter materially with wear. Not the least 
of the merits of the sleeve valve is found 
in the fact that it lends itself to positive operation by eccentric 
mechanisms, which are in every way greatly superior to the non¬ 
positive cam mechanisms universally used to actuate poppet valves. 

A very good example of this latest type of Knight motor is 
illustrated in Fig. 16, showing the intake side of the Moline-Knight 
four-cylinder motor. 

Sliding Valves. Sliding valves of other than the sleeve type, 
embracing a considerable variety of piston valves and valves similar to 
those employed in steam engines, have not found as much favor with 
designers of automobile engines as have other types herein referred to. 



Fig. 17. Single-Cylinder, Rotat¬ 
ing-Valve Anzani Engine 
International Copyright 


193 



34 


GASOLINE AUTOMOBILES 



One exception is the successful use of a “split-ring” valve, sliding 
up and down in the cylinder head just above the piston, which has 
found successful application in a few motors recently built by the 
Renault Company, of France. 

Rotating Valves. A rotating valve of characteristic type is that 
employed in the single-cylinder engine illustrated in Fig. 17, which 
is an experimental motor designed by Anzani, famous as the designer 
of several European automobile motors, and of the aviation motor 
with which Bleriot effected the first flight across the English Channel 


Fig. 18. Sections of Darracq Rotating Valve Motor, Showing Intake Position (left) 
and Exhaust Position (right) 


This motor is provided with a plain rotating sleeve in the cylinder 
head, turned at a constant speed by skew gears. 

Other rotating valves that have proved successful are the 
Darracq valve, illustrated in Figs. 18 and 19, and various rotating 
inlet valves used on the crankcases of two-cycle motors. 

The Darracq rotating valve is a particularly clever example of 
sound designing, and exhaustive tests have proved it thoroughly 
successful and reliable. 

Much of its merit undoubtedly inheres in the fact that the 
port through which it communicates with the cylinder is closed by 
the piston at the top of the stroke, so that at the moment of explosion 








GASOLINE AUTOMOBILES 


35 


the valve is shielded from the highest temperatures that occur within 
the cylinder. 

An American motor of somewhat similar general form has a pair 
of these valves on opposite sides of the cylinder head, driven, how¬ 
ever, by silent chains. The only difference in the action from that 
described and illustrated is the simplification and reduction of sizes 
made possible by having the exhaust on one side and the inlet on the 
other. 



Fig. 19. Complete Darracq Rotating Valve Motor 
This Photograph Protected by International Copyright 


Half-Time Shafts. For the actuation of the valve mechanism 
of any four-cycle motor, it is necessary to have a shaft (or in the case 
of rotary valves, to run the valve itself as a shaft), turning at one-half 
the speed of the crankshaft through a two-to-one gear ratio. 

Ordinarily the half-time shaft is the camshaft, but in motors 
of the Knight type it is, of course, an eccentric shaft. Camshafts par¬ 
ticularly call for good workmanship and high-grade materials, as w r ell 
.as sound design, since the constant pounding of the valve stems 
or push rods on the cams is a prolific source of trouble, if anything 
but the soundest of sound construction be employed. 

The most important recent innovation in this detail of auto¬ 
mobile mechanism is the driving of half-time shafts by silent chains 


195 



36 


GASOLINE AUTOMOBILES 


in place of the long-used gearing, of spur and helical type. By this 
improvement the noise of the gears is eliminated. 

A typical silent chain running over a pair of gears may be seen 
in Fig. 20. These, however, present very broad-faced gears, while 
the usual timing gears would have a narrow face. In the use and 
action of the silent chain, this makes little or no difference. In the 
Cadillac motor, shown in Fig. 9, a pair of these is used, one driving 
the camshaft from the crank¬ 
shaft while the other drives 
the auxiliary shaft from the 
camshaft. In the American 
form of Knight sliding-sleeve- 
valve motors shown in Fig. 

16, a pair of silent chains is 
used for the eccentric shaft 
on one side and the electric 
generator on the other. These 
are driven from a pair of 
sprockets set side by side on an extension of the crankshaft. 

A point that should be brought out in connection with silent- 
chain camshaft driving is that the use of the chain allows the shafts 
to be placed anywhere desired, and thus, to a certain extent, frees 
the designer from the former restriction of a two-to-one reduction 
ratio in the gears, which rather fixed the size, and consequently the 
position of the gears. This had an influence also upon cylinder 
design, as the center of the camshaft fixed the center of all the valves— 
that is their distance from the center line of the motor. 



Fig. 20. Silent Chain and Sprockets 


WATER COOLING 

Though nearly all successful automobile motors, as well as most 
other internal-combustion engines, are water-cooled, there is so 
much obvious fault to be found with this system of securing a result 
—involving first the generation of heat and then its waste by a com¬ 
plicated refrigerating system, instead of its utilization by converting 
more of the heat units into useful work—that it is scarcely credible 
that water cooling can persist indefinitely. 

Water Jacketing. The first essential in water-cooling a motor 
is to provide the cylinders with water jackets, through which the 


196 



GASOLINE AUTOMOBILES 


37 



cooling water is circulated in contact with the outsides of the walls 
within which the heat is liberated. 

Water jackets are of two types, integral and built-up. The latter 
system of construction, though adding to complication and conducive 


to leakage, permits of lighter construction, besides diminishing the 
likelihood of hidden flaws in the cylinder castings, which with cored 
jackets are not likely to reveal themselves until they cause break¬ 
down, perhaps after the engine has been long in use. 


Fig. 21. Wolseley Aviation Motor with Attached Water Jackets 
This Photograph Protected by International Copyright 


38 


GASOLINE AUTOMOBILES 


Integral Jackets. With integral jackets the usual system is to 
form the jackets by cores, in the founding, so that there are no open¬ 
ings in the jackets except those for removing the core sand and wires, 
and for connecting the pipes of the circulating system. In many of 
the best examples of motor design, however, the core openings are 
left very large but with plane faces, and are closed by screwed-on or 
clamped-on plates, thus making the construction practically a 
compromise between the completely integral and the completely 
built-on jackets. 



Fig. 22. Gregoire Aviation Motor with Attached Water Jackets 


This Photograph Protected by International Copyright 


For example, in such modern construction as that shown in Fig. 
9, a large plate will be noted on the ends of the cylinders. This 
covers a tremendous core hole, by the use of which the internal 
construction of the water jackets is made practically perfect in the 
foundry. This also allows easy inspection and cleaning, the removal 
of the two end plates enabling a person to see right through the water 
jacket from end to end. This latter-day construction overcomes all 
objections previously raised against troubles with complicated water 
jacket cores. In fact, designers of large block castings for cylinders, 
like the one shown in Fig. 12, etc., were forced to take measures of 


198 











GASOLINE AUTOMOBILES 


39 


this kind for self-protection, although in this connection, it is no more 
than fair to state that foundry men have made just as rapid advances in 
the art of casting automobile-engine cylinders and other complicated 
parts, as the designers of machines have made in every other way. 

Built-On Jackets. In Figs. 21 and 22 are shown two character¬ 
istic examples of built-on water jackets, the jackets of both of these 
motors being made of sheet metal, formed around the cylinders, 
and attached to flanges left on the cylinder casting by closely placed 
small screws. 

The type of attached copper water jacket referred to on page 26, 
however, is generally considered superior to that shown in Figs. 21 
and 22, because in the former case there are avoided the screws, the 
jacket being simply a hollow shell forced over the cylinders and held 
by ring-like clamps at the two ends. This greatly reduces the lia¬ 
bility to leakage. 

An important advantage of applied jackets of the type just 
described is their freedom to yield in case the water freezes in them. 
Thus is eliminated the danger of cracked cylinders, which not infre¬ 
quently result from exposure to cold weather in ordinary automobile 
motors having jackets integral with the cylinder. 

A particularly neat method of water-jacketing, which has been 
applied with some success abroad, consists in the electrodeposition 
of copper jackets on the cylinders, through the use of wax molds, 
to produce the desired forms. Jackets thus applied, though some¬ 
what expensive, are said to be practically indestructible and com¬ 
pletely proof against leakage. 

Radiators and Piping. It has often been pointed out that all 
cooling of automobile engines is in reality air cooling, the water- 
cooled motor being simply one in which the heat units to be disposed 
of are conveyed from the cylinders by the circulating water, to be 
then dissipated in the air that passes through the radiator, instead 
of directly lost in air passing over thin flanges cast on the cylinders. 
A water-cooling system therefore constitutes a sort of indirect air 
cooling. This being the case, the chief justification for water cooling 
consists in the margin it allows for much greater cooling areas in 
contact with air than it is possible to provide by mere extensions of 
the cylinder surfaces themselves. 

The total cooling area of the radiators employed in automobiles 


199 


40 


GASOLINE AUTOMOBILES 


will range all the way from ten to ninety square feet, the latter being 
not unusual in the best type of honeycomb radiators, with hexagonal 
openings and very thin water spaces. 

The smaller areas are found in the cheaper types of radiators 
built up of straight, round, or flat tubes, and provided with fins to 
increase the area exposed to the air. Radiators of these types, unless 
very large, are often inadequate to cool a motor when it is laboring 
under continued heavy usage, as in pulling on the low gear through 
deep sand or mud, or up long, heavy grades. Under such conditions 
a motor that may have run for months without any cooling trouble 
whatever in level country, will often boil all of the water out of the 
cooling system within a few minutes. 

The piping of automobile cooling systems is in a great many 
cars made too small to afford free circulation, and this mistake in 
design, common in the earlier days of automobile engineering, is 
one that cannot be too carefully avoided. 

In the experience of most automobile designers, the most satis¬ 
factory method of connecting up the piping of a circulating system 
is found in the use of ordinary steam hose, clamped around the ends 
of the pipe by small metal straps. 

Considered an improvement over this by a few designers is the 
use of steam hose for practically the entire piping system, doing away 
with metal piping altogether except as this is needed close up to 
radiator and water jackets for the attachment of the hose. 

Circulation. An unobstructed and vigorous circulation of the 
water in a cooling system is a great factor in reducing the size of 
radiator required, and in preventing overheating and boiling away 
of the water. 

Pumps. The usual method of circulating the cooling water is 
to use one type or another of small pump, driven by suitable gearing 
from the engine itself. 

Gear pumps are often used for this purpose, because of their 
extreme simplicity, but it is difficult to make them large enough to 
handle as great volumes of water as most designers now regard as 
desirable. 

The consequence is that the centrifugal pump is now the type most 
preferred. In their best forms centrifugal pumps consist of simple 
multibladed “impellers”, revolving with close clearances in a housing. 


200 



GASOLINE AUTOMOBILES 


41 



One advantage of the centrifugal pump is that if any small 
objects, such as a stick or pebble, should by any chance get into the 
circulating system—though strainers always should be provided to 
prevent this contingency—no serious harm is likely to result, whereas 
with a gear pump breakage is almost certain to ensue. 

Chiefly in motorboat motors, of the two-cycle types, recipro¬ 
cating plunger pumps are used to circulate the cooling water. The 
Volume of water handled by pumps of this type, of dimensions that 
can be conveniently employed, is not very large, however, and it is 


Fig. 23. Renault Motor with Thermosiphon Circulation 
This Photograph Protected by International Copyright 


only the fact that the water is not re-used and is, therefore, cooler, 
and of a consequent greater effectiveness, that makes possible the 
use of plunger pumps in motorboats. 

Thermosiphon. Circulation of the cooling water by the thermo¬ 
siphon action, due to the heated water in the jackets rising and the 
cooled water in the radiator descending, is the practice of an increas¬ 
ing number of designers, and has been demonstrated to be very 
effective with liberal jacket spaces and large-diameter piping. 

The pioneer and still the most prominent exponent of thermo- 


201 



42 


GASOLINE AUTOMOBILES 


siphon cooling is the Renault Company, of France. A typical 
Renault motor-and-radiator combination, with thermosiphon circu¬ 
lation, is illustrated in Fig. 23. 

Cadillac System. An entirely new idea in the control of the 
temperature of the cooling water is that used on the new eight- 
cylinder Cadillac motors. Here, each block of four cylinders has its 
own circulating system, with pump and piping, entirely distinct from 
the other. In each one, on top of the pump housing, is located a 
thermostat, like that shown in Fig. 24. This controls the movement 
of a valve, which when shut off prevents the flow of water to the 
radiator. That is, when the temperature of the water falls below a 
certain figure at which the thermostat is set, it comes into action and 
cuts off the flow of water 
from the radiator to the 
pump. The result is that 
the pump can circulate 
only that part which 
comes through the very 
small pipe to the inlet 
manifold and carbureter, 
and from there back to 
the pump. This contin¬ 
ues until the water be¬ 
comes heated; the raising 
of the temperature oper¬ 
ates the thermostat which 
opens the valve, and the system is again complete. In the upper 
right-hand part of this figure is shown in outline the circulating 
system of one block of cylinders. 

Fans. In the earlier days of automobile designing it was 
deemed sufficient to secure circulation of air through the radiators 
by the movement of the car alone. This was soon found inadequate, 
however, since often at the times when most cooling was needed, 
as in hill climbing or hard pulling on the level, the car would be 
moving at its lowest speed on low gear, with the result that the air 
draft through the radiator was not sufficient to cool the water. 

This condition was remedied by the use of a fan behind the 
radiator, driven by a belt or gearing from the motor, so as to draw 



Fig. 24. Thermostatic Device in Latest Cadillac Water- 
Cooling System to Preserve Equilibrium and 
Even Temperature 




202 





















GASOLINE AUTOMOBILES 


43 


a constant draft through the radiator in proportion to the speed of 
the engine rather than of the car. 

Nowadays practically all automobile power plants are provided 
with fans, the only exceptions being a few very small motors, in which 
the difficulty of cooling is not so great as with the higher powers. 

In some cases, instead of a separate fan, fan blades are placed 
on the flywheel, and so made to induce a draft through the bonnet 
that covers the engine, thus avoiding the necessity for the addition 
to the moving parts involved in the usual fan system. Such a fly¬ 
wheel fan is used in the engine illustrated in Fig. 23. 

A later plan of even greater effectiveness is the housing-in of 
the whole rear end of the radiator, so that what air passes through 
must pass through the center where the fan is located. This is but 
another way of saying that all air must pass through at a high 
velocity, and, therefore, large quantities must pass through, which 
insures efficiency. This plan fulfills one requirement of air cooling, 
either direct or indirect—that is, the large quantity of air which must 
be used. 

Anti=Freezing Solutions. In using automobiles in very cold 
climates in the winter months there is great danger of the water in 
the cooling system freezing when the car is standing still, or even 
with the motor running slowly if the temperature be very low. The 
result of such freezing is almost certain injury to the cylinders, 
through cracking of the water jackets, as well as the probability of 
bursting out radiator seams, with consequent leakage. 

To avoid these difficulties it is not uncommon to use, instead 
of pure water, one kind or another of anti-freezing solution, usually 
compounded by the mixture of some chemical with water, to lower 
its freezing point. Thus, glycerine or alcohol mixed with water will 
keep it from freezing at all ordinary winter temperatures. Glycer¬ 
ine is somewhat objected to because of its sticky, gummy nature, and 
also because of its deleterious effects upon the rubber hose of the 
piping system. Alcohol will, if not replenished from time to time, 
evaporate out of the water and thus permit it to freeze, or, if mixed in 
too great a quantity, it may introduce a fire risk otherwise avoidable. 

A much favored anti-freezing solution consists of calcium 
chloride dissolved in water, in quantity proportioned to the tem¬ 
peratures that it is desired to guard against. 


203 


44 


GASOLINE AUTOMOBILES 


All anti-freezing solutions are more or less objectionable in that 
they are more likely than pure water to corrode and clog up the cir¬ 
culating system, and there is no doubt that the elimination of the 
necessity for them, by the substitution of air cooling for water 
cooling, will mark a great advance in automobile development. 

AIR COOLING 

Though successfully employed in one or two automobiles, and 
remarkably developed in some of its applications to aviation motors, 
air cooling is not considered by most engineers to be successfully 



Fig. 25. Six-Cylinder Air-Cooled Motor Used in the Franklin Car 


applicable to the average automobile. That it will become more 
practical in the future, however, is the opinion of many. 

Unfortunately, this is an instance where the better and simpler 
method does not meet with popular approval. That is, the cooling 
of automobile cylinders is one of those cases in which the best in 
theory is not by any means accepted practice. The extent to which 
the public has adopted water cooling as compared with air cooling 
may be noted in these figures for 1916: Cooled by air, 1 car; cooled 
by water, 168; total, 169. 

Flanges and Fins. The usual method of air cooling, successfully 
employed in aviation and motorcycle motors and in a few automo- 


















GASOLINE AUTOMOBILES 


45 


biles, is to provide the cylinders with fins or flanges for increasing 
the area of the surface, supplementing this with means for blowing 
large volumes of air over the surfaces thus provided. 

Air Jackets. Several of the most practical examples of air¬ 
cooled motors in aviation constructions are ones in which, in addition 
to the flanges or fins on the cylinders, these are surrounded by air 
jackets to concentrate the drafts of air that effect the cooling. 

Blowers and Fans. The most successful air cooling has been 
accomplished, as has already been explained, by types of blowers 
capable of inducing much more vigorous air currents than are com¬ 
monly drawn through the radiators of water-cooled automobiles by 
the types of fans in common use in power plants of that character. 

In the Franklin, the most successful air-cooled automobile 
motor, a side view of which can be seen in Fig. 25, the cooling is a 
sort of combination of the flange method and the blower method. 
The fins are vertical and radial, with a close-fitting hood connected 
to an air-tight pan. At the only opening in this hood, which is at 
the rear end, is placed the fan (on the flywheel). This draws the 
air past the cylinder walls, where it is needed. 

Internal Cooling and Scavenging. Perhaps more promising as 
a road to final and universal use of air cooling are the systems of 
pumping air through the interiors instead of blowing it over the 
exteriors of the cylinders. Such internal cooling—in addition to’ 
directing the maximum cooling effect where it is most needed, on 
the oil-coated surfaces that are exposed to the heat of combustion— 
has the further advantage that it may be made to scavenge out all 
residual exhaust gases, which, besides helping to accumulate heat, 
also act so detrimentally upon the functioning of ordinary motors. 
This is a direct result of the admixture of retained exhaust gases 
with incoming fresh charges. 

Methods of internal cooling and scavenging that appear of 
definite promise are those proposed in various recent schemes for 
pumping air first into the crankcase—either by using the under side 
of the piston as a pump, as in common two-cycle construction, or 
by applying special pumps to the crankcase for this particular pur¬ 
pose—the air thus pumped being then transferred into the cylinders 
by means of by-passes, with the result that it exerts a positive cooling 
effect inside of the cylinder. 


46 


GASOLINE AUTOMOBILES 


In England, some interesting experiments have been made on a 
theory of internal cooling in which water is introduced into the 
cylinders, in the form of a spray, at certain points in the cycle. This 
is said to add power, in addition to helping the cooling. 

CARBURETION 

Function of the Carbureter. As has been pointed out in the 
general outline of the motor car, the first and most important thing 
in the engine cycle is to get the fuel into the cylinders. This is done 
through the medium of the carburetion system, the principal unit 
in which is the carbureter. The function of this is to convert a 
liquid—gasoline—into a gas—gasoline vapor—measure this, and add 
to it the right quantity of air to give proper and complete combustion. 
If this be not done, power is lost, either through the use of too much 
or too little air. In the latter case, not all the fuel is vaporized, hence 
some of it is wasted. 

This sounds like a simple proposition, yet its very simplicity has 
been the undoing of many automobile experts. The vaporizer 
becomes more and more complex each year, constant additions and 
changes are being made in the other parts of the system, and in other 
ways the carburetion system shows a constant change. Despite all 
this, few fundamental laws have been found to be in error, and few 
new ones have been discovered or developed. 

Effect of Heavier Fuels. For some years past there has been 
under way a subtle change in the character of the fuel—the gasoline 
used for the propulsion of automobiles. The small production and 
the increasing demand have combined to render almost unpurchas- 
able, except at high prices and then from large dealers, the lighter 
and more volatile gasolines of some years ago. In the place of them 
there have been quietly introduced much heavier petroleum dis¬ 
tillates, which evaporate less readily—though they are actually of 
higher value in terms of power units. This condition has compelled 
several changes in the carbureter problem. 

In addition to the foregoing, in some parts of the world there 
have been serious efforts made to utilize in automobile motors 
alcohol and benzene (not benzine), which, with proper provision for 
their carburetion, constitute excellent fuels. 


GASOLINE AUTOMOBILES 


47 


The most important of the changes dictated by this development 
in the fuel situation is the now general practice of heating the float 
chambers of carbureters, either by water from the circulating system 
or by exhaust gases. An alternative scheme is the drawing of the air 
for the carbureter from a point adjacent to the exhaust piping, so 
that this air is sufficiently warmed to take up readily the gasoline 
necessary to constitute with it a proper explosive mixture. 

Fuel Injection. Systems of fuel feeding by direct injection of 
minute quantities of the combustible liquid into the cylinders, or 
into the intake piping, have been advocated or experimented with 
for many years, and have found very successful application in station¬ 
ary and flight engineering, though as yet not one of these systems has 
successfully competed with the carbureter in automobile service, 
where the conditions of power variation are such that fuel injection 
has not seemed readily applicable. 

Nevertheless, there are many engineers who adhere to the view 
that sooner or later fuel injection will supplant present systems of 
carburetion, and progress made recently with aviation motors of fuel- 
injection types may seem in some measure to justify this view. 

Despite the success of this system on aeroplane and stationary 
engines—notably on the Antoinette and the Diesel, respectively— 
there is not to the writer’s knowledge a single American motorcar 
manufacturer now using or experimenting with fuel injection. A few 
years ago a motorcar brought out in the Middle West used it, but 
this was short-lived. Since then, nothing has been done. 

IGNITION 

To no portion of the automobile power plant has more study 
been devoted than has been bestowed upon the ignition system. 
And yet in spite of the thousands of dollars that have been expended 
and the innumerable systems that have been tried, it probably is 
safe to assert that there remains no element of the complete auto¬ 
mobile power plant that is more prolific of trouble than some of the 
ignition systems that are still in use. 

Low Tension and High Tension. There are two principal types 
of ignition systems in common use for automobile engines. The 
essential distinction between these lies in their use of low-tension 
or high-tension current. 


207 


48 


GASOLINE AUTOMOBILES 


Low Tension. A typical low-tension system is shown in Fig. 26. 
A is the battery (a magneto, a dynamo, or any other suitable source 
of current may be used), B is a spark coil, and C, D, and E are the 
elements of a make-and-break device that is mechanically actuated 
at regular intervals by the motor itself to produce the sparks within 
the cylinder. As shown in the drawing, the circuit is completed by 
grounding the wires from one side of the battery on the cylinder base, 
or any other portion of the machine, as at F. In the construction 
sketched D shows a small insulated plug entering the interior of the 



Fig. 26. Diagram of Low-Tension Ignition System 


cylinder, usually through one of the valve caps, while C is a movable 
arm that makes and breaks contact with D, at the point E, when 
it is given a slight rocking movement. For the best results this 
rocking movement must be very sharp and rapid, in the nature of a 
snap, and it must, of course, be correctly timed to occur in proper 
relation to the moment when the spark is required. 

Many different systems have been devised and used for the 
effective and reliable operation of make-and-break devices of the 
character illustrated, but the most reliable usually prove to be 
the simplest. 

The chief advantage of low-tension ignition is its immunity 
from troubles caused by short circulating by leakage of the current 
through poor insulation, or across moistened terminals. This con¬ 
sideration has caused it to be extensively employed in motorboat 


208 
























GASOLINE AUTOMOBILES 


49 


motors, where there is much exposure to water, but for automobiles 
high-tension ignition is almost universal, though there are one or 
two prominent manufacturers who remain staunch adherents of low- 
tension ignition. 

High Tension . A system of high-tension ignition is diagrammed 
in Fig 27, in which A is the battery—or other suitable current 
source—placed in a primary circuit that [also includes the contact 
maker C, the primary winding of the coil B, and the vibrator E. 

The contact maker C is positively driven by a connection with 
some revolving part of the motor, so that it makes contact at the 
exact time ignition is required in each cylinder. 



With a system of the type described, when contact is made the 
first result is attraction of the vibrator blade E by the magnetized 
core H of the coil. This, by drawing E away from the contact screw 

G, at once breaks the primary circuit again, and this demagnetizes 

H, with the result that E again springs into contact with G. The 
effect of this is to cause a rapid series of current surges through the 
coil B, as long as the contact maker C maintains the contact. 

Each time a surge of primary current passes through a coil a 
secondary current of very high voltage is induced in the secondary 
circuit, which is grounded on the cylinder at F and connected at B 
with the spark plug. This plug, for high-tension ignition, has an 
open gap of about ^ inch at 7, across the resistance of which gap the 
current wdll jump, because of its high tension. 

Ignition is thus effected by a rapid succession of sparks across L 


209 































50 


GASOLINE AUTOMOBILES 


Magnetos. The magneto, Fig. 28, is a mechanical means of 
creating electric current, and as such eliminates the need of frequent 
attention to storage batteries, their occasional filling and changing 
and the constant bother and trouble with acids. In substance, the 
magneto is a small generator with field magnets of the permanent 
type, constructed of hard steel, instead of the more usual wire wound 
form. In one car, the Ford, the magneto is of this wire-wound type, 
but is incorporated in the flywheel. 

The construction of the ordinary magneto is such that it must be 
rotated at one set speed, and in a particular relation to the crank¬ 
shaft. Usually the universal 
coupling through which it is 
driven is so marked that it 
can easily be put back cor¬ 
rectly, but in removing and 
replacing it the repairman 
should be careful to note 
its position, and whether it 
is marked or not. 

In all ignition forms the 
need for “advancing” the 
ignition, or causing the spark 
to occur earlier in the cycle, 
is taken care of. With the 
high-tension magneto, the contact breaker is rotated against the 
direction of rotation of the armature, except in one particular make, 
the Mea, in which the whole armature is rocked. This method 
gives a greater range of advance, and it is claimed, a hotter spark 
as well. In low-tension forms, particular battery ignition systems, 
the timer is advanced in approximately the same way as the 
magneto contact breaker. 

With the discovery several years ago that two sparks in a motor’s 
cylinders would produce greater power, a number of magnetos have 
been brought out with double distributors, one placed at one end of 
the armature, the other at the other. 

Similarly, the tendency toward higher speeds of the last-year 
and the introduction of eights and twelves has brought out many 
improvements and innovations in ignition. For one thing, it has 



Fig. 28. Bosch Enclosed Type Magneto 


210 


GASOLINE AUTOMOBILES 


51 


been found in the high-speed eights and twelves that magneto ignition 
is not satisfactory because of the magnetic lag. This in turn has 
induced great improvements in battery ignition, more particularly 
in distributors. It is a notable fact that in 1916 for the first time 
since the magneto was introduced, more than half the cars, 54 per 
cent, are battery-ignited. 

This wider adoption of battery ignition, especially for higher 
speed work, has necessitated similar improvements in vibrators, 
contact breakers, coils, spark plugs, and wiring. 

Among the plugs, the multiple point form seems to be losing 
ground in favor of the better made single point form. So much more 
dependable has ignition become that very few cars now have the dual, 
duplex and other forms so widely used at one time. 

LUBRICATION 

A first condition of reliability and continued service in any type 
of motor is the positive and unfailing lubrication of its bearings. 

In automobiles it is particularly important that the lubrication 
be of a positive and foolproof character, requiring a minimum of 
attention to assure its certain operativeness. 

Interior and Exterior Demands. The engine of a motor car 
requires two distinct kinds of lubrication. The interior parts which 
are subjected to the greatest heat and rotate or slide at the highest 
rate of speed, and generally do the greatest amount of work, must 
have what amounts to a continuous stream of good lubricant. With 
the exterior parts, which do not rotate so fast, do less work, are not 
subjected to much heating and will be kept cool by the atmosphere 
as well as the cooling air drawn in by the fan, there is no need for this 
continuous stream, nor for such a quantity of lubricant. The elimi¬ 
nation of these two strenuous conditions has an influence on the 
quality of lubricant which may be used. 

This being the case, the two systems must be considered sepa¬ 
rately. With reference to the internal oiling, there are two general 
systems in use: the pressure form and the splash type. A third, which 
is now coming rapidly into use, is a combination of the two, called 
the splash-pressure system. In 1915, the relative popularity of these 
three was as follows: pressure—on 40 motors; splash on 80; splash- 
pressure—on 39; total 169. 

In the pressure form (or its modification, the splash-pressure), 


211 



52 GASOLINE AUTOMOBILES 

the pressure may be produced in a number of ways—by a single large 
pump; by a series of small pumps, one for each bearing lead; or by a 
reservoir or tank kept filled by a separate pump (gravity pressure). 

Pressure Feeding. A very successful and one of the best types 
of lubrication systems is that in which the oil is fed under pressure 
to the different bearings. 

Splash-Pressure. In the splash-pressure system the oil to all the 
crankshaft and connecting-rod bearings, to the timing gears, and to 
the upper portion of the cylinder walls is supplied through the medium 


Fig. 29. Pressure Feed Lubrication System on Pierce-Arrow Cars 
Courtesy of Pierce-Arrow Motor Car Company , Buffalo, New York 

of a gear-oil pump driven usually by worm gearing from the camshaft. 
The other bearings within the engine are lubricated by oil spray 
thrown from the crankshaft. Such a system is shown in Fig. 29. 

Single Pump. The drilled crankshaft, as shown in Fig. 29, is a 
necessity in all pressure systems, as it is also in all combination 
splash-pressure systems. This can be seen, and perhaps the whole 
system explained more clearly, by referring to Fig. 30. In this the 
single pump working direct is used, thus differing from the reservoir 
system explained above. This diagram shows also how the oil is 
forced to flow through the three bearing leads to the interior of the 


212 



















GASOLINE AUTOMOBILES 


53 


crankshaft, whence it follows in to the pins upon which the connect¬ 
ing rods work. These rods are drilled, and the oil is thrown out by 
centrifugal force, passing up through the rods to the piston, thence 
onto the cylinder walls. In addition, the latter are sure to receive 
sufficient lubricant, for the rotating shaft and rods throw off a good 
deal in the form of a mist which settles upon the cylinder walls. 

Generally, pockets are provided inside the motor to catch the 
mist and force it to flow to the camshaft and other bearings, besides 
the crankshaft, but in this case, it will be noted that the camshaft 



Fig. 30. Lubrication System of the Cadillac Eight, Showing Pump and Path 
of the Oil, Also Auxiliary Circuit for Camshaft 


bearings have individual supplies through the medium of a camshaft 
oiling pipe. 

An objection to lubricating systems of this type is that, in case 
there are several leads to different bearings, one of them may become 
obstructed without anything to indicate this condition or to over¬ 
come it, until the bearing involved becomes overheated and ruined. 
This is because, if one lead becomes obstructed, the oil can still 
continue to feed out through the others, thus relieving the pressure 
in apparently the normal manner, and so failing to reveal a serious 
derangement. 


213 







54 


GASOLINE AUTOMOBILES 


Individual Pumps. To avoid the objection just stated, the expe¬ 
dient of feeding the oil by individual pumps, independently driven 
and capable of individual adjustment, enabling them to feed any 
desired, amount of oil to any particular bearing regardless of the 
amount that may be fed to any other bearing, has been widely 
applied. In such a system, if obstruction of any one of the leads 
should occur, such obstruction is practically certain to be forced out 
by the action of the pump, which in all lubricating systems of estab¬ 
lished type is made capable of working against enormous pressure. 

One of these lubricators, made for eight feeds, is shown in Fig. 31 . 
By extending the casing and the longitudinal shaft inside, and add- 



rig. 31. Detroit Eight-Feed Multiple Oiler as Used for Motor 
Lubrication 


Courtesy of Detroit Lubricator Company, Detroit, Michigan 


ing more pumps, this type is capable of extension to any desired 
number. The eight-feed form shown allows of one lead to each of the 
three main bearings of a four-cylinder engine, one each to the four 
cylinder walls, with a lead remaining for the gear case, at the front 
of the motor. 

Gravity Feeding. Feeding of oil by gravity to one or more bear¬ 
ings is a method that has been employed with some success, but it is 
now encountered only in rare instances in automobile power plants. 

Splash Lubrication. The feeding of oil to bearing surfaces by 
the simple expedient of enclosing a quantity of it in a reservoir in 
which the working parts are also contained is a successful and 
widely used scheme in automobile motor construction. 


214 



GASOLINE AUTOMOBILES 


55 


In this system, as will be shown in detail later, the lower ends 
of the connecting rods “splash” up the oil which is in the bottom 
of the crankcase in the form of a huge puddle. Since this method, 
formerly almost universal, has been criticised as wasteful of oil, as 
well as productive of much needless smoke, it has been modified by 
the majority of makers so that the scoops on the ends of the connect¬ 
ing rods dip into small narrow troughs, provided for this purpose. 
Another objection to this system is that at high speeds, too little oil 
is thrown around the interior of the cylinders and crankcase since 
the initial rotation of the rods has churned or beaten the entire 
supply into a mist, while at low speeds too much is thrown around 
for the work the engine is doing. 

This latter objection has been overcome in later engines by mak¬ 
ing the troughs, into which the connecting-rod scoops dip, movable 
and attached to the throttle lever, so that when the latter is opened 
wide to develop maximum power, the troughs are brought up higher, 
allowing the scoops to dip do'wn deeper, and thus supply a greater 
amount of lubricant. 

External Lubrication. In the lubrication of the external parts 
of the motor, such as the pump shaft, magneto shaft, oiler shaft, fan 
shaft, generator shaft, air pump and shaft, etc., an entirely different 
method of lubrication is needed—one that is more 
simple in every respect, allows the use of more 
simple lubricating devices, and does not require 
anything like the care and adjustment previously 
pointed out as needed for the internal parts. 

Oil and Grease Cups. Chief among the devices 
used for lubricating these outside parts, are oil and 
grease cups, the latter in increasing quantities, the 
former decreasing. Formerly, oil cups were much 
used, but they gave poor satisfaction, collected 
dirt, and were unsatisfactory generally. In the use 
of grease cups, there are but three things to observe: 

They should be large enough, accessible, and easily 
filled. 

For application to spring eye-bolts there is a particular type 
of grease cup. This grease cup is of the type that feeds through being 
occasionally screwed up a small distance as the bearing uses up the 



Fig. 32. Typical Screw 
Type Grease Cup with 
Wing Handle 
Courtesy of Lunken- 
heimer Company , 
Cincinnati, Ohio 



56 


GASOLINE AUTOMOBILES 



Fig. 33. Lunkenheimer 
Grease Cup with Re¬ 
movable Barrel 


lubricant, and its positive action is rendered more certain by the use 
of a detent (not illustrated) that holds the cover in any position in 
which it may be left. The grease is contained in the entire cap which, 
when unscrewed from the lower portion, is readily 
and conveniently filled by scooping up the grease. 

A form quite generally used is the simple 
cup shown in Fig. 32. This is a screw-compres¬ 
sion cup, in which the lubricant is forced out by 
screwing down on the reservoir. This form is 
prevented from coming loose by the compression 
spring here shown very much compressed below 
the ratchet, which governs the screwing down 
of the top or reservoir. To fill this, the ratchet 
portion is held down and the top screwed off, 
turning in the reverse of the usual direction. 

Although the top is fitted with a wing handle 
it can hardly be considered easily refilled. 

Another widely used form is seen in section in Fig. 33. This has 
a larger handle and in this respect may be considered easier to fill. 
A type which is rapidly coming into use and has all the advantages of 
the other two, and more, is shown in Fig. 34. 

This is a plain screw type with a large handle, 
but the cap is of sheet brass and is sprung into 
place. As this is sprung off by the plunger 
inside, when screwed away out, filling is reduced 
to a matter of seconds. The plunger screws all 
the way in and affords pressure all the way.. 

The simplest form of oil cup has a hole 
in one side, which is covered with a spring- 
held cover. To use it, the cover is lifted with 
the fingers until the hole is uncovered, then 
the point of the oil can is inserted and the oil 
forced in. 

Oils and Greases. The variety of oils and 
greases recommended for automobile use is so extensive, and there are 
so many cheap and worthless lubricating compounds on the market, 
that it is almost impossible for the purchaser without technical knowl¬ 
edge to discriminate between them. The various tests from time to 



Fig. 34. L u n k e nheimer 
Grease Cup with Spring 
Cover for Quick Filling 







GASOLINE AUTOMOBILES 


57 


time recommended, whereby the user may ascertain for himself the 
quality of the lubricant he is using, are rarely of positive value, since 
the compounders of the shoddy oils and greases are usually sufficiently 
expert chemists to concoct admixtures that will successfully pass 
such simple tests as are available to the average layman, and will fail 
only under the more critical analysis of a competent chemist, or under 
the severe and more risky practical demonstration that results from 
long use, in the course of which the worthlessness of the lubricant is apt 
to be found out only at the cost of serious injury to the mechanism. 

The consequence is that the only really safe policy to follow is 
the purchase of the highest grades of oils and greases, marketed by 
concerns of established reputation. 

The oils generally found best for gasoline-engine cylinder lubri¬ 
cation are the mineral oils derived from petroleum, though castor 
oil is found to possess peculiar merits for the lubrication of air-cooled 
motors working at high temperatures, and in which there is often 
involved the friction of steel surfaces working over steel surfaces. 
This oil is exclusively employed in aviation motors, such as the 
Gnome, which is built with steel cylinders and pistons, and it is 
often utilized in racing automobile motors. Its chief merit seems 
to be that instead of withstanding the high temperatures, which is 
the result sought in the use of mineral oils of high fire test, it burns 
up clean without leaving any deposit upon the cylinder walls. It has 
to be fed in excessive quantities, which makes its use a rather expen¬ 
sive method of lubrication. But for the peculiar services for which 
it is adapted, it certainly proves most satisfactory. 

In greases and oils used for the lubrication of parts not exposed 
to such high temperatures as prevail in gasoline-engine cylinders, the 
admixture of vegetable and animal greases and oils with mineral oils and 
greases is not objectionable and often may be of considerable benefit. 

Graphite is a solid lubricant that it is very advantageous to 
employ in many parts of an automobile. In the deflocculated form, 
admixed in very small percentages with cylinder oils, gearbox greases, 
etc., there is no question but what it greatly conduces to smooth 
running and to long life of bearings. Its resistance to the very 
highest temperatures makes it constitute a considerable safeguard 
against immediate injury in case of neglect to replenish the lubri¬ 
cants as often as is properly required. 


58 


GASOLINE AUTOMOBILES 


Principles of Effective Lubrication. To render lubrication 
positive and effective there are certain conditions regarding the 
design of bearings and the feeding of lubricants that must be scru¬ 
pulously observed. 

The proper application of a lubricant to a revolving shaft, 
passing through a bearing, requires that definite space be provided 
between shaft and bearing for the lubricating material. The amount 
of this space varies with the size of the shaft, the speed of rotation, 
and other conditions, but in a general way it can be specified that 
the space must be greater as the shaft diameter increases, and greater 
for heavy oils and low speeds than for light oils and high speeds. 
For the crankshafts of automobile engines, to take a specific example, 
it is rarely desirable to have the bearing smaller than from .0005 
to .0015 inch larger than the shaft. The annular space thus pro- 



Fig. 35. Condition of Bearing for Proper Lubrication 


vided, as suggested at A in the end and sectional views in Fig. 35, is 
occupied by the lubricant, which, contrary to another general impres¬ 
sion, will not be squeezed out unless the shaft is loaded above its 
capacity, which is more apt to occur from the bearing area being 
too small than from any other condition likely to be encountered. 

With the bearing area large enough—which means that the 
specific pressure on its projected area must not be excessive—the 
tendency of the oil to remain in its place by capillary attraction, 
perhaps helped by the pressure under which it is fed into the bearing, 
is much greater than the tendency of the load upon the shaft to force 
it out. 

From the foregoing, it will now be evident that the condition 
of effective lubrication is that in which the shaft literally floats in 
an oil film of microscopic thickness, this film completely surrounding 
it and so protecting it from any contact whatever, under normal 
conditions, with the bearing surface. Wherefore the necessity for 


218 











GASOLINE AUTOMOBILES 


59 


accurate fitting of bearings is not to secure a close metal-to-metal 
contact, as is sometimes erroneously supposed, but to provide the 
necessary oil film of a uniform, instead of an irregular, thickness. 

BEARINGS 

Types of Bearings Required for Different Locations. As the 

portion of a mechanism upon which, more than upon any other 
element, its continued operation and long working life depends, the 
bearings of any piece of machinery should be of the most approved 
design and most perfect construction. The crankshaft and connect¬ 
ing-rod bearings, which are the most important on the motor, are of 
the plain type on the majority of engines. Of the 1914 cars but six 
different makes had ball bearings for the motors, and of these, two 
used plain bearings on other models, so that only four makers actually 
believed in ball bearings for engine shafts. For camshafts there is 
more difference of opinion, while on fan shafts almost all makers use 
balls. As for the other shafts, as pump, oiler, magneto, air-pump, 
generator, etc., these are generally of the plain, solid, round type. 

Engine bearings, however, are generally of the split or halved 
type, the upper and lower halves being practically duplicates. A 
reason for this construction appears as soon as one considers the 
application of the bearings to the shaft. It is granted that a crank¬ 
shaft must be as firm and solid as possible, and hence it must be made 
in one piece. As ball-bearings also are made in one piece, there arises 
at once the difficulty of getting the bearings into place on the one- 
piece shaft. This difficulty has necessitated cutting the shaft or else 
making it especially large and heavy in those cases where balls are 
used. With the split type of bearing there are no troubles of this kind 
and, in addition, the bearings are adjustable for the inevitable wear. 

Plain Bearings. The conditions that determine the proper 
proportioning and fitting of plain bearings have already been referred 
to in a preceding paragraph. 

The materials of plain bearings are commonly varied to meet 
different conditions. With liberal bearing areas, and in situations 
where it is desired to bring about a perfect fit with minimum amount 
of labor, and in addition to this to protect the shaft from wear in 
case there is failure of the lubrication, the various types of babbitt 
metal—which usually are alloys of tin and lead, with sometimes 


219 


GO 


GASOLINE AUTOMOBILES 


some admixture of antimony and other alloys—are widely regarded 
as the most serviceable. Probably the greatest advantage of a bab¬ 
bitted bearing is that, should the lubrication fail, the low melting 
point and the soft material of the bearing will insure its fusing out 
without injury to the more expensive and valuable shaft. 

Brass and bronze bearings, particularly the phosphor bronzes 
and the bronzes in which the proportion of tin is high and that of 
copper low, with sometimes the admixture of a proportion of zinc 
or nickel, will allow the use of materially higher pressures per square 
inch than can be safely permitted on babbitted bearings. 

Steel shafts in cast-iron bushings, and even in hardened-steel 
bushings, make much better bearings than one might think, and 
though immediate trouble is to be anticipated with such a bearing 



Fig. 3G. Timken Roller Bearing 
Courtesy of Timken Roller Bearing Axle Company 

should its lubrication fail, even momentarily this is more or less true 
of any bearing that can be devised. And since steel-to-steel and steel- 
to-cast-iron permit much the highest loadings to the unit of area that 
are permissible with any types of metal-to-metal bearing, the merits 
of these materials are perhaps less appreciated than might be desir¬ 
able. Steel pins through steel bushings, however, are a not uncommon 
construction for the piston-pin bearings in high-grade engines. 

Roller Bearings. Roller bearings, constituted by "the inter¬ 
position of a number of small rollers between shafts and casings, 
are a type of bearing widely employed in automobiles. 


220 






GASOLINE AUTOMOBILES 


61 


A much-favored construction is the tapered roller bearing 
illustrated in Fig. 36. This stands up very well under both thrust 
and radial loads. 

Another type of roller bearing is that illustrated in Fig. 37 and 
shown in position on a car’s rear axle in Fig. 46. This is one in which 
the rollers are small flexible coils made of strip steel, finally hardened 
and ground accurately to size. This type of roller can be depended 
upon to work without breakage or injury even though there be con¬ 
siderable deflection or inaccuracy in the alignment of shaft or casings, 
the flexibility of the individual rollers taking care of such small 
errors. 



Fig. 37. Hyatt Flexible Roller Bearing Partly Disassembled to Show Components 
Courtesy of Hyatt Roller Bearing Company, Newark, New Jersey 


Referring to Fig. 37, it will be noted that there is a solid steel 
shell to go on the shaft and fit it tightly, and another to fit into the case 
or support, whatever it may be, perhaps attached there permanently. 
Between these two comes the cage carrying the flexible rollers. Any 
load imposed upon the shaft is transmitted to the inner sleeve and by 
it to the flexible rollers; these rollers absorb the load so that none of it 
reaches the outer case. Furthermore, shocks coming to the case 
from without are absorbed by the flexibility of the rollers and vice 
versa, shocks to the shaft do not reach the case. 

Ball Bearings. Probably the best of all bearings, except for 
certain special applications in which it is difficult to utilize them in 


221 





62 


GASOLINE AUTOMOBILES 


sufficiently large sizes to assure durability, are the annular ball 
bearings of the general type illustrated in Figs. 38 to 42, inclusive. 
The basic feature of the most successful of modern annular ball 
bearings is their non-adjustability, 
the balls being ground very accu¬ 
rately to size, and closely fitted be¬ 
tween the inner and outer races so 
as to allow practically no play, but at 
the same time without any arrange¬ 
ment whatever for adjustment such 
as was provided in the earlier cup- 
and-cone bearings of bicycle practice. 

The reason that the best ball 
bearings are not made adjustable is 
that, in any conceivable type of ball bearing, one or the other of 
the races rotates and the other remains in a fixed position. The 
result is that there must be a loaded side to the race that does not 
rotate, with the consequence that when wear occurs, it wears the 
ball track deeper at this point than on the unloaded side. And, 
with the bearings thus worn, and any provision for adjustment, the 
attempt to adjust can result only in tight and loose positions as the 
balls come in and out of the spot that is more deeply worn. 

This condition has led the designers and manufacturers of the 
various types of high-grade annular ball bearings that are now on the 
market, to discard adjustment as of no value, and to substitute in 
its place qualities of material and hardness of surface which, in 
combination with the provision of sufficient sizes, are found to reduce 
wear to so small an amount that it is almost inappreciable. A 
bearing thus made can be therefore depended upon to outlive almost 
any other part of the mechanism in which 
it is placed. 

The carrying capacities of ball bear¬ 
ings, as compared with those of roller 
bearings, are much greater than a casual 
consideration might lead one to suppose. 

Theoretically, the contact of a roller bearing—between a roller and 
one of the races—is a line contact, while that between a ball and a 
ball race is a point. But practically, since some deformation occurs 



Fig. 39. Section of Annular 
Ball Bearing 



222 



















GASOLINE AUTOMOBILES 


63 


in even the hardest materials under sufficient load, the line contact 
in the roller bearing becomes a rectangle and the point contact in 

f 


Fig. 40. Ball Cage of Annular Ball Bearing 

the ball bearing becomes a circle. Now the vital fact is that the 
area of the rectangle in the one case is substantially equal to that of 
the circle of the other—with given quality of materials and a given 
loading. So a ball bearing is fully as capable of carrying high loads 
as a roller bearing, besides which it avoids the risk of breakage that 
usually exists with rollers, because of the impossibility of making 
them perfectly true and cylindrical. 

To assemble ball bearings of the type illustrated in Fig. 39, either 
of two expedients may be adopted. One is to notch one or both of 
the ball races, so that by slightly springing them a full circle of balls 
can be introduced through the notch. The other scheme is to employ 
only enough balls to fill half of the space between the races, which 
permits them to be introduced without any forcing, after which they 




are simply spaced out at equal intervals and thus held by some sort 
of cage or retainer, such as is illustrated in Fig 40. 
















64 


GASOLINE AUTOMOBILES 


Ball bearings of the common annular type are quite serviceable 
to sustain end thrust as well as radial loads. For the best results 
under such loads, however, it is essential that the load be distributed 
equally around the entire circle of balls, for which reason the system 
illustrated in Fig. 41 is a means of avoiding the unequal distribution 
of pressure apt to result from the slightest inaccuracy of fitting. In 
this construction the outer ball race, shown at A, is provided with 
a spherical outer surface, permitting it to rock slightly in the mount- 
into the position shown in an exaggerated degree at B. It 
thus floats automatically to a position at exact right angles to the 
shaft upon which it is mounted; and so insures even loading of the 
whole ball circle. 

An annular ball bearing designed for thrust loads alone is illus¬ 
trated in Fig. 42. In this the lower race A is provided with a spherical 
face, described from the radius B, so that, as in the case of the bearing 
illustrated in Fig. 41, when in use it automatically floats under the 
load into such a position that all of the balls are under equal pressure. 

To secure uniformly satisfactory results from ball bearings it is 
not only necessary in the first place to have them of the best materials, 
accurately made, and of sufficient sizes, but thereafter they must be 
always protected from dust and grit, and from water and acids which 
tend to cause rust. Also, they must be kept lubricated. 

TRANSMISSION elements 

Of quite as great importance as the development of power at 
the motor is its effective and efficient transmission to the driving 
wheels. Because of certain inherent shortcomings of the gasoline 
motor—its lack of flexibility, its inability to pull at low speeds, etc 
—the problem of power transmission is no simple one, and has taken 
much solving to bring it to its present state of perfection. 

Clutches. The fact that a gasoline engine is not self-starting 
and that it is so inflexible that to propel a car at varying speeds 
requires the ratio between engine revolution and wheel revolution to 
be changed by the intervention of gearing, renders necessary a clutch 
for disconnecting the transmission from the motor during starting 
and gear shifting. 6 

. Cone Clutches - Consisting of a simple leather-faced cone let 
into a seat machined in the flywheel, the cone clutch was the type of 


224 



GASOLINE AUTOMOBILES 65 

clutch first successfully applied to automobiles of modern type, and 
it still remains the one favored by many manufacturers and users. 

Multiple-Disk Clutches. Because of a greater durability, due 
largely to the ability to enclose them in oil-containing housings, 
multiple-disk clutches have in many cars supplanted the cone clutch. 
In its simplest form a multiple-disk clutch consists of a pack of 
ring-like adjacent elements, every alternate one of which is connected 
by lugs first to the driven and then to the driving member. Obviously, 
with this arrangement, by letting the whole pack of disks be loose 


Fig. 43. Multiple-Disk Clutch and Four-Speed Transmission of Latest Winton Cars 
Courtesy of Winton Car Company , Cleveland, Ohio 

no transmission of power can take place, but when the disks are 
compressed together by springs the friction of their adjacent surfaces 
will cause one set to drive the other. 

An excellent example of this can be seen in Fig. 43, although 
this is presented for the purpose of illustrating sliding-gear trans¬ 
missions, mentioned later. Here the disk clutch is enclosed in the 
case with the transmission, and practically forms a unit with it. This 
is of the oiled form consisting of all-metal plates, not lined, the 
springs serving to squeeze the oil out from between them and thus 
produce a gradual engagement. 


225 















6G 


GASOLINE AUTOMOBILES 


As a matter of fact, the dry-disk clutch is gaining ground at the 
expense of all other forms. This does not run in oil, but is kept 
perfectly dry; instead of an all-metal contact, leather, asbestos 
composition—such as is used for brake lining—or other similar 
heat-resisting, long-wearing compound materials are used on one or 
both sides of the metal. This has been found by experience to give 
better results than the oil clutch, particularly after the clutch springs 
in the latter type have been used for a considerable length of time, 
when great difficulty is experienced in getting them to squeeze out the 
oil between the metal plates quick enough to give satisfactory results. 

Miscellaneous Clutches. Clutches of various expanding and 
contracting types, similar to expanding and contracting brakes, are 
favored by a few designers of high standing. 

Change=Speed Gears. The use of gearing for positively varying 
the ratio between engine revolutions and wheel revolutions has so 
far proved superior to all other methods. 

Sliding Gears. Though long decried by technical critics as 
“brutal engineering”, sliding gears have vindicated the foresight of 
their originators by becoming the standard present type, to the 
almost total extinction of all alternative devices. Made of good 
materials and stepped down in ratios not too abruptly varying, they 
can be made to afford reliability and durability both truly remark¬ 
able, considering the small proportions generally used and the large 
amounts of power often transmitted. 

As mentioned above, Fig. 43 presents an excellent example of 
modern sliding-gear transmission, this being a gearbox which gives 
four speeds forward and one in reverse. A notable point about it is 
that the third speed is direct, the high speed being geared-up for use 
only in emergencies. 

Planetary Gears. Though now used in only a very few cars, the 
planetary gear can be designed so as to render good service, and a 
point that particularly commends it is the certainty that in the 
hands of even the most incapable or careless operator it is not 
possible to strip the gear teeth, which are always in mesh, and the 
different combinations of which are brought easily into engagement 
by the gradual application of brake bands. 

The type of planetary gear used on the Ford automobiles, of 
which many thousands are in use, is illustrated in Fig. 44. As the 


226 


GASOLINE AUTOMOBILES 


67 



Fig. 44. Ford Planetary Gear Transmission 
Courtesy of Ford Motor Company, Detroit, Michigan 



Fig. 45. Silent-Chain Gear Transmission Used on Maudsley Cars 


227 





















68 


GASOLINE AUTOMOBILES 


product of long experience in designing this type of a gear, and with 
the further experience back of it that has been accumulated in the 
use of over nine hundred thousand cars, it is safe to say that this 
gear represents the most advanced practice in the design and con¬ 
struction of its particular type. 

Individual-Clutch Gears. Though never extensively used, the 
class of gear in which the pairs of gear wheels are always in mesh, 
but are brought into action only by individual clutches—either of 
the gradually applied brake or disk type or of positively engaging 
jaw type has some features of conspicuous merit. 

Another individual-clutch gear of much interest is that illus¬ 
trated in Fig. 45, in which the drives from one shaft to another are 
wholly by silent chains. The chains in this gearbox, which is that 
of the English Maudsley car, not only are of a strength impossible 
to secure with gears, but in addition work with most exceptional 
silence. In exhaustive tests made with this type of change-speed 
gear on the motor omnibuses in London, it is claimed that the results 
secured were in every way superior to those to be had with direct 
gear transmission. 

Miscellaneous Gears and Operation. There seems to be a clear 
and growing field for the electrical transmission which will replace 
the so-called “brutal” action of sliding-gear forms. In those which 
have been developed, both a generator and a motor are used, the 
former replacing with its armature the usual flywheel, while the litter 
takes the place of the transmission. This combination has a number 
of advantages; for example, an almost unlimited number of speeds 
is possible, including more than one reverse, and in emergencies it 
is possible to utilize the full power of the engine and that of the 
motor, too, through the medium of the necessary battery, thus giving 
an excess of power even beyond the full output of the engine. With 
the gradual but persistent change toward electricity in the modern 
car, it would not be strange to see this type come to the front in a 
few years. 

Even now, the electrically operated sliding-gear transmission 
is an accomplished fact, a number of makers having used this for 
1913, continued it for 1914, and, augmented by others, continued it 
for 1915. In this, the usual levers are omitted, the shifting being 
done by means of a series of buttons on the steering wheel or grouped 


228 


GASOLINE AUTOMOBILES 


G9 


below it. With this type of transmission it is also possible to antici¬ 
pate speed needs, setting to an expected speed before the actual 
need arises. This is an advantage which no manual form of sliding 
gear can give, although the air-operated transmission affords the same. 

Universal Joints. To allow for the movement of the axle, in 
the cases of shaft-driven cars, and to take care of slight frame dis¬ 
tortion, affecting the alignment between gearbox and motor even in 
chain-driven cars, universal joints at suitable points in the shafting 
are a proved necessity in all automobiles of any pretense to quality 
or sound design. 

Usually, in shaft-driven cars there is a universal joint only at 
the forward end* of the propeller shaft, or perhaps at this point and 
also at a point adjacent to the rear axle. The use of some sort of 
universal joint between clutch and gearbox is also very common. 

However, it is becoming more and more the practice to use a 
considerable number of square joints which have a certain amount 
of flexibility, in place of a few universals. The squared joint gives 
fore and aft freedom with greater simplicity and less cost. In Fig. 43 
there will be noted a slip or sliding joint on the engine side and a 
full universal joint on the side toward the rear axle where the driving 
shaft connects. 

Final Drives. Possible types of final drive, from the gearbox 
to the rear axle and the driving wheels^or from the motor to the 
gearbox, in case this is mounted on the rear axle, as is not uncommon 
practice—are practically limited, in cars of sound design, to shaft 
and double-chain constructions. 

Shaft Drive . In its usual form, shaft driving in an automobile 
involves simply a propeller shaft interposed between the rear axle 
and a revolving shaft in the car, above the spring action. There is 
further involved some provision for taking the torque of the shaft and 
of the axle, so that these shall maintain their proper relative positions. 

It is an objection to this type of drive that the reaction of the 
revolving shaft tends to tilt the whole car on its springs in a direc¬ 
tion opposite to that in which the shaft is turning. In some cars 
this is counteracted by the use of slightly heavier springs on one 
side. The advantages of the shaft drive are the complete enclosure 
of all working elements, with their consequent protection from dirt, 
and the assurance of their proper lubrication. 


229 


70 


GASOLINE AUTOMOBILES 



Fig. 46. Ford Final Drive, Differential, and Axles 


In Fig. 46 is illustrated the final drive of the Ford automobile 
in which the end of the propeller shaft is shown at A, together with 



Fig. 47. Worm and Worm Gear for Rear Axle, Showing Upper Position of Worm 
Courtesy of Timken-Detroit Axle Company, Detroit, Michigan 


230 






GASOLINE AUTOMOBILES 


71 


the bearings in which it revolves, the pinion by which it drives the 
car, the axle, the differential, and the bearings of the floating inner 
elements of the axle. 

The shaft drive does not necessarily include the use of bevel 
gears for the final reduction at the rear axle; in fact, almost any form 
of gears may be used. In one well-known shaft-driven commercial 
car, the final gears consist of a pair of plain spur gears, while on 
the shaft of the second of these gears is a pair of bevels. 

As soon as the bevel 
gear final reduction dis¬ 
closed its limitations and 
disadvantages, designers 
started to displace it. 
One of the earliest forms 
of gear used for this pur¬ 
pose was the worm, an 
example of which can be 
seen in Fig. 47. This 
shows the worm placed 
above the wheel, but the 
lower position, which is 
also used, has the advan¬ 
tage of copious lubrica¬ 
tion. In the form shown, 
the wheel must come di¬ 
rectly beneath the worm, 
so that the differential 
may be set inside of it. 

A later form, which 
is designed to replace the 
straight bevel, is the spiral bevel. This is primarily a bevel gear 
with spiral teeth, the idea being to incorporate in the bevel gear the 
advantages of the spirally shaped worm tooth, without its disad¬ 
vantages. As Fig. 48 shows, this makes a very compact and neat 
arrangement, the differential fitting within the larger gear in 
the same manner as with the worm. 

Double-Chain Drive. The use of double chains, by which the 
driving wheels of an automobile are driven from a countershaft 



Fig. 48. Spiral Bevel Gears—a New Noiseless Type 
for Rear Axles 

Courtesy of Timken-Detroit Axle Company, 
Detroit, Michigan 


231 






72 


GASOLINE AUTOMOBILES 


across the frame of the machine, is a practice possessed of a number 
of advantages. But because of the noise and quick wear with badly 
designed chain drives and the difficulties of completely enclosing the 



Fig. 49. Typical Roller Chain 


driving mechanism, chains are not now as popular as formerly. 
Nevertheless, the elimination of universal joints working through 
large angles and under heavy loads; the avoidance of heavy weights 



Fig. 50. Typical Silent Chain 


carried on rear axles without spring support; the lowering of the 
clearance by the differential housings, etc., are very real objections 
that the double chain avoids. 



For trucking and other heavy service, chains are still commonly 
in use, and it is the belief of many that better understanding of their 
merits, and the means of securing these merits in positive and per¬ 
manent form, will result in their more general use. 











GASOLINE AUTOMOBILES 


73 


A typical roller chain, of the type most used for automobile 
drives, is illustrated in Fig. 49. 

Silent chains, of the types illustrated in Figs. 50 and 51, possess 
certain points of superiority over roller chains and so are coming 
increasingly into use for camshaft drives, in gearboxes, etc., and there 
is some possibility that they will find more extensive application than 
at present to final drives. 

The action of a silent chain is illustrated in Fig. 51, in which it 
is seen that as the chain links enter the sprocket teeth, the chain 
teeth jat the same time close together and settle in the sprocket with 
a wedging action that causes them to be absolutely tight, but without 
any more binding than there is backlash. 

To keep silent chains from coming off sidewise from the sprockets 
over which they run, it is customary to make the side links of deeper 
section than the center links, as is illustrated in Fig. 50. Another 
successful scheme is grooving the sprocket to receive a row of special 
center links in the chain, which are made deeper than the standard 
links. 

Differential Gears. The need of a differential or “balance” 
gear, to permit the driving, while at the same time avoiding a rigid 
connection between the two rear wheels, will be readily appreciated 
when it is realized that in all but straight travel one of the rear 
wheels must turn faster than the other. Differential gears are the 
common means of permitting this, though, of course, in certain types 
of friction transmissions, and in electric, hydraulic, and other trans¬ 
missions in which there is individual driving of the wheels by devices 
more or less non-positive in their character, the need for a differential 
is avoided. 

A typical bevel differential gear is shown in Fig. 46, which is 
sectioned so as to bring it out clearly. The differential arrangement 
in Figs. 47 and 48 has also been mentioned. 

Miscellaneous Transmissions. Of the means other than purely 
mechanical that have been employed for transmitting the power 
of an automobile motor to the driving wheels, among the most 
successful are various types of electric, friction, hydraulic, and 
pneumatic transmissions. 

Friction Drive. For light vehicles, in which the power trans¬ 
mitted is not very great, and for service in level country, certain 


233 


74 


GASOLINE AUTOMOBILES 


types of friction drives have been found quite successful. Their 
absolute foolproofness, rendering them perfectly immune from 
damage at the hands of even the most incompetent drivers, is greatly 
in their favor. 

Hydraulic Drive . Among the hydraulic drives, the most success¬ 
ful is the Manly, a system that is fully described elsewhere herein. 

RUNNING=GEAR ELEMENTS 

In arranging a logical presentation of the multifarious details 
that combine to constitute modern automobile engineering, it is 
convenient to treat the running gear as distinct from the body, the 
power plant, and such portions of the mechanism as are involved in 
transmitting the power from motor to wheels. 

Frames. The part of an automobile to which all other parts 
are attached, or upon which they all depend, is the frame. In most 
modern machines—though wood and steel tubing were much experi¬ 
mented with in earlier years—the frames are made of pressed steel, 
built up of two side sills formed up in channel section, and then con¬ 
nected by cross members of similar section, riveted or autogenously 
welded with liberal gusset plates in the corners. 

The most approved of present practice demands that the depth 
of web and the thickness of material vary with the size of the machine, 
from the thin and small sizes used for light pleasure cars up to the 
massive steel beams employed in the heaviest trucks. It is also 
usual for the frames to be narrowed at the front, to permit greater 
lock to the wheels for short turning, and a drop between the axles 
is generally desirable to allow liberal spring action without placing 
the body unduly high. 

The underslung frame, at one time looked upon with great 
favor, has practically disapppeared. There were a number of reasons 
for this. For one thing, the apparent low center of gravity was not 
real; similarly, the apparent high clearance with low body-placing 
was not what it seemed; finally, the springing gave much trouble. 
The firms which advocated this construction two and three years 
ago either have disappeared, or else their engineers have experienced 
a change of heart. At any rate, this very promising and much 
exploited feature is not now used on American cars. Foreign design¬ 
ers never did take it up e 


234 


GASOLINE AUTOMOBILES 


75 


Springs. Even on the smooth surface afforded by steel rails, 
a vehicle running at high speed will quickly pound itself to destruc¬ 
tion unless as much of the weight as possible above the wheels be 
carried on yielding springs, to cushion the shock between wheels and 
load. In an automobile, then, which must run on rough roads, the 
provision of the most responsive, elastic, and durable springs that 
can be made is particularly necessary. 

Leaf Springs. The familiar type of spring in almost universal 
use on automobiles and horse vehicles and extensively employed in 
railway cars is the leaf spring. Properly proportioned to the loads 
they have to carry, and suitably and securely mounted, leaf springs 
afford all the spring action that can be desired and, if made of the 
best alloy steel, their breakage is very infrequent. 

Present automobile practice is almost unanimous for semi- 
elliptic springs in front, but for the rear springs opinion is divided. 
Several years ago designers w T ere just as unanimous for the semi- 
elliptic rear, but a gradual change has come about in the last two 
years. The three-quarter and seven-eighths elliptic have, to a large 
extent, replaced the half form, although a few makers still favor the 
platform arrangement, while the newer cantilever is claiming an 
increasing number of adherents. For small cars, too, a modification of 
the cantilever in the form of a quarter-elliptic is found to be efficient 
and low in price, as well as light in weight—all desirable qualities. 

If any prediction were to be made in this connection as to future 
popularity of the various forms, the present outlook would favor the 
three-quarter elliptic and the cantilever forms to share about equally 
the rear situation, while the front may be expected to remain almost 
entirely semi-elliptic. In small cars there seems to be an increasing 
tendency toward the quartered-elliptic or semi-cantilever. 

Coil Springs. Springs of the coil type are of less present impor¬ 
tance than they are of future promise. The great advantage of 
coil springs is that their smaller and compacter size renders prac¬ 
ticable the carrying of one or two extra springs in a toolbox, in addi¬ 
tion to which, if properly designed, they can be relied upon to afford 
a most perfect action. That there are no difficulties in the way of 
making coil springs of sufficient size for automobiles is abundantly 
attested in the fact that they are used on Pullman and other railroad 
cars quite commonly. The first firm to apply coil springs success- 


235 


76 


GASOLINE AUTOMOBILES 


fully to automobile use was the Sizaire-Naudin concern of France. 
In this country, practically the only maker who ever gave more than 
a passing thought to the coil spring as a car suspension, has gone out 
of business and the car has not been manufactured for more than 
three years. Even in its last year this car was put out in two forms, 
one with leaf springs, the other with the coils. A reason for this lies 
in the fact that a well-known shock-absorber company claimed to 
have patents which covered this use of coil springs, and insisted upon 



Fig. 52. Front Springs on a Pierce-Arrow Limousine, Showing the 
Westinghouse Air Cylinders in Position 


this company taking out a license under those patents. This they 
were not willing to do. 

Shock Absorbers. With the gradual increase in the size and 
weight of cars, problems in springing have come up which were 
undreamed of previously. In springing a heavy car so that none of 
the small road shocks reaches the occupants of the body, it was found 
that the very rough spots brought forth a considerable jounce, in 
fact an actual shock. To obviate this condition, shock absorbers 
in a number of different forms have been brought out, the idea of 


236 



GASOLINE AUTOMOBILES 


77 


all being to absorb the sudden movements caused by considerable 
inequalities in the road surface. 

These consist of coiled spring forms, with the springs working 
vertically, at an angle, and otherwise; of auxiliary leaf springs; of 
flat rotating friction plates working one over the other; of combina¬ 
tions of leather straps and coil springs tending to wind the straps 
around pulleys, or other similar combinations; of coil springs 



Fig. 53. I-Beam Axle and Connecting Rod of Detroit Car 
Courtesy of Anderson Electric Company, Detroit, Michigan 


working in conjunction with liquids; of liquids alone; and, not by 
any means the least, of air cylinders. An example of one of the last- 
named type is shown in Fig. 52, which indicates the application of 
the air-cylinder form to the front springs of a Pierce-Arrow 
limousine car. 

AxleS. Automobile axles, like all other elements of the auto¬ 
mobile, demand for the best results, the best of materials and of work- 



Fig. 54. Inverted Semi-Elliptic Rear Axle Springs Used in Ford Cars 
Courtesy of Ford Motor Company, Detroit, Michigan 


manship. That these are especially necessary in axles, however, 
is due to the fact that axle failure is almost certain to result in serious 
accident. 

I-Beam Axles. This is the term applied to the common forged 
type of front axle with a cross section like a capital letter I. The 
best axles of this type are forged from high-grade alloy steel, as in 
the example illustrated in Fig. 53. 









78 


GASOLINE AUTOMOBILES 


Pressed-Steel Axles. Steel stampings, assembled by riveting, 
bolting, or welding, are found widely serviceable for automobile 
rear-axle housings of the types through which the wheels are driven 
by the combination of propeller shafts, gears, and floating inner-axle 
members. 

An axle that is one of the cheapest to produce, one of the strong¬ 
est in service, and which perhaps demanded as heavy an initial 
investment as any in the preparations for its manufacture, is that 
illustrated in Fig. 55. This axle, which is used on a well-known 
American car, is made in two parts, each stamped and drawn out of 
a steel disk, and the two elements then joined at the center by bolts. 

Particularly ingenious in connection with this axle is the use of 
a transverse rear spring, by wdiich the load of the vehicle is carried 
almost into the plane of the wheels, so that it imposes only the very 
slightest bending strain on the axle. 

Tubular Axles. Axles made of steel tubing, either with or 
without the reinforcement of a vertical strip of steel pressed into 
them, have been extensively used in the past by the various auto¬ 
mobile manufacturers, but are now generally discarded by the more 
progressive designers. 

Wheels. As probably the oldest principle in mechanical engi¬ 
neering, and certainly applied to vehicle construction centuries upon 
centuries before Christ, if the testimony of Egyptian hieroglyphics 
and the excavations of archeologists are any criterion, it would seem 
that the vehicle wheel should have developed very close to finality, 
not only because of its simplicity but also because of the time it has 
had to develop. Yet the activities of inventors more diligent than 
well informed are still directed to the devising of all manner of spring 
wheels and other freak constructions in the mistaken hope of thus 
doing away with the necessity for pneumatic tires. 

Wood Wheels. Wood wheels, of the artillery type, are by far 
the most used on automobiles. The difference between this type of 
wheel and that generally employed in horse vehicles is that the com¬ 
mon type of carriage and wagon wheel has the spokes staggered in 
the hub, whereas, in the artillery wheel, the spokes are bolted between 
two hub flanges, without staggering. The latter construction is 
found preferable for wheels with pneumatic tires, and the “dishing”, 
on which so much stress is often laid by wheelwrights, becomes of 


233 


GASOLINE AUTOMOBILES 


79 


little importance with the combination of workmanlike construction, 
small diameters, and the use of pneumatic tires. 

Wire Wheels. Wire wheels, which have the spokes in tension 
instead of in compression, as in all other types, are the lightest, 
strongest, and the most elastic that can be made. Abundantly 
tested in the development of the bicycle, 
and thereafter applied to the first automo¬ 
biles, wire wheels were subsequently dis¬ 
carded because of their appearance, rather 
than because of any sound engineering rea¬ 
son. The fact that they are somewhat 
more difficult to clean than wood wheels, 
however, may also have had some influence 
in forcing their disuse. 

Latterly there are signs that the wire 
wheel is coming back, and particularly in 
England and on the Continent, where man¬ 
ufacturers find greater difficulty in secur¬ 
ing good second-growth hickory than in the 
United States, and where the advantages 
of the various types of “demountable” 
wheels—quickly removable from the thim¬ 
ble hubs upon which they are locked—are 
more appreciated, it is rapidly regaining 
its former place in popular favor. 

A typical [wire wheel showing the de¬ 
velopment of the triple spoke to strengthen 
the wheel and to take care of side strains, 
is illustrated in Fig. 55. 

Disk Wheels. In Fig. 56 is shown an 
interesting example of disk wheel, built up 
of two pressed-steel plates that are fastened together at the rim and 
at the hub. This wheel construction, besides being the easiest of 
all to clean and keep clean, affords as much strength as can be had 
with any other type, with less weight than with wood wheels, and 
with but sligh tly more than with wire wheels. The disk wheel is also 
the cheapest to manufacture, so there are good reasons for supposing 
that it may dispute with the wire wheel for supremacy. 







80 


GASOLINE AUTOMOBILES 


In addition, disks have been developed for application to both 
the wood wheel and the wire form. On the former, it is simply a 
matter of some persons liking the appearance of a flat surface, but on 
the latter it has a real advantage in that it eliminates the cleaning 
of the spokes, a task which many persons dislike so much that they 
will not use wire wheels for that single reason. As these disks are 
easily and quickly applied, and add little or no weight to the total, 
they give all the advantages of the wire wheel and the appearance of 
the disk wheel, plus the lack of cleaning. 

Brakes, Important both as an engineering problem and because 
of their relation to safety, the brakes of automobiles have been the 
subject of much study and 
experiment. 

Expanding and Constrict¬ 
ing Brakes . These are the 
common type, usually acting 
on drums bolted directly to 
the driving wheels. In the 
expanding type of brake the 
construction involves shoes 
contained in the drum, capa¬ 
ble of being forced out by 
simple mechanism into con¬ 
tact with the inside of the 
drum. In the constricting 
type the brake is applied by a band that draws tight around the 
outside of the drum. 

Transmission Brakes. Brakes acting upon propeller shafts, 
countershafts, or elsewhere in the transmission of an automobile, 
possess the advantage that, acting on parts that revolve at higher 
speeds than the wheels, their action is more effective. The objection 
to them lies in their racking the driving elements, thus causing much 
wear. They seem to be coming back into use, however. 

Brake Facings. A great variety of materials are used for the 
wearing surfaces of brakes. There are the plain metal-to-metal con¬ 
structions, as of cast-iron shoes against steel drums; of copper bands 
around steel drums; and there are the various organic facings, of 
one kind and another of beltings and other materials riveted to the 



240 



GASOLINE AUTOMOBILES 


81 


brake shoes or bands. The best among the beltings are those of 
asbestos with a mesh of copper wire, since these cannot be destroyed 
by overheating. Very effective, but subject to destruction by char¬ 
ring from prolonged application, are the fabric facings. 

Miscellaneous Braking Devices. There are various means of 
retarding a car by causing it to drive a geared-up air fan revolving 
under the body. Such schemes of braking are of some advantage in 
making long coasts in mountain country, such prolonged descents 
being seriously destructive of ordinary brakes unless a water drip 
is provided to minimize the heating and the consequent wear. 

Brake Control. Automobile brakes are variously operated by 
hand levers and foot pedals, the usual arrangement being that of 
a foot pedal to the right of the clutch and accelerator pedals, with 
an “emergency” brake lever at the right, in close proximity to the 
change-speed gear lever. 

Tires. Probably the greatest invention and the most important 
element in the automobile is the pneumatic tire, without which the 
motor-driven road vehicle, as we know it today, would be practically 
impossible. 

Pneumatic Tires. The function of the pneumatic tire is almost 
as widely misunderstood as are its merits and its care. The really 
fundamental function of the pneumatic tire is its adaptation to the 
irregularity of the road surface, and not, as most persons suppose, 
a cushioning of the load by the provision of a spring action. 

Conversely, the shortcoming of the steel or other hard tire is 
not its inelasticity but its lack of deformability. The consequence 
is that as a hard tire rolls along any surface of other than perfect 
smoothness, it must either climb over, crush, or force down all of 
the minute inequalities it encounters. Thus on a gravel road a steel 
tire expends energy in crushing gravel, in pressing small pebbles 
into the hard surface beneath them, and in every other way but 
in contributing to the efficient forward movement of the vehicle. 

A pneumatic tire, on the other hand, by virtue of its deformable 
surface yields to every inequality, wasting energy neither in crushing 
pebbles nor in lifting the machine, and thus it establishes a sort of 
floating compromise between all the high and low spots in the road, 
thereby affording the substantial equivalent of an ideally perfect 
surface to begin with. The perfect elasticity of the confined air, 


241 


82 


GASOLINE AUTOMOBILES 




which quite incidentally does afford a considerable spring action, is of 
high importance simply as a means of causing the tire instantly to 
recover its normal shape as 
it leaves the road that has 
momentarily deformed it. 

From the foregoing it 
will be understood how mis¬ 
taken are all projects in the 
way of spring wheels and the 
like, which are based upon 
the supposition that the func¬ 
tion of the pneumatic tire is 
that of a spring, when as a 
matter of fact its service as 
a spring is only incidental to 
its more fundamental func¬ 
tions. 

The size of tires is a point 
of more importance than is 
generally understood. The 
proper measure of tire cost 
being cost per mile, the fact 
that a larger wheel diam¬ 
eter requires fewer revolu¬ 
tions for a given distance 
traveled means not only 
that the larger-diameter 
wheel strikes holes and in¬ 
equalities less abruptly, but 
also means that the tire at 
any point makes that many 
less complete road contacts 
in going a given distance, 
thus reducing its exposure 
to wear, heating, etc. 

Large tire sections are 
as important as liberal diameters, because with a small tire section, 
unless the tire is inflated to an unduly high pressure, it proves totally 


Fig. 57. Goodyear Universal Q. D. Dunlop 
Type of Tire and Rim 


Fig. 58. Typical Q. D. Demountable Rim and 
Tire Equipment 


242 





GASOLINE AUTOMOBILES 


83 


incapable of carrying the load, whereas with a tire sufficiently large to 
carry the load without undue deformation, even at a more moderate 
pressure, the working stresses are vastly lower. 

To secure the maximum of tire service, amateur repairing by 
the roadside should be absolutely eliminated. The best way of 
eliminating it is the use of demountable rims or wheels, or quick- 
detachable rims, whereby the ready replacement of tubes and casings 
is facilitated, and the temptation to run on damaged tires is done 
away with. 

Typical pneumatic tires and rims, of approved and standard 
forms are illustrated in Figs. 57 and 58. 

Although the tire and rim situation has been in a chaotic condi¬ 
tion for the past few years, the manufacturers of these products are 
getting together with the Standardization Committee of the Society of 
Automobile Engineers, with the result that a project is now complete 
to reduce the number of tire and rim sizes from 59 to 9, with nine 
additional oversizes which would fit the same rims. That is, there 
would be but 9 rim sizes and 18 tire sizes. 

Cord Tires. The latest development in pneumatic tires is the 
so-called cord form. In this the usual fabric body is replaced by a 
woven member which consists of cotton cords impregnated with 
rubber. These are laid down so as to pass diagonally across the 
tread of the wire. Their size varies from approximately ^ inch 
in diameter in one form up 'to perhaps & inch in another. The 
cord tire is supposed to give these advantages: Greater resiliency, 
longer life, less susceptibility to punctures, less road friction which 
is practically an increase in engine power, greater carrying capacity, 
gasoline saving, additional speed, greater mileage, easier steering, 
practical immunity to stone bruises. This is a formidable list 
of claims, but practically all the best cars are now equipped with 
this form. 

Cushion Tires. Solid rubber tires without fabric or air in them 
are rather more durable at low speeds than pneumatic tires, and on 
the good surfaces of city streets, under cars of low speed, they pos¬ 
sess in addition to their durability a reliability and immunity from 
punctures that render them preferable for certain classes of com¬ 
mercial and electric vehicle service. 

Demountable Rims. The demountable rim has fully as large 


243 


84 


GASOLINE AUTOMOBILES 


an influence as any other feature upon the matters of tire satisfaction, 
comfort in use and in replacement, actual mileages, cost, etc. 

These have gradually replaced all other tire and rim forms, until 
now, practically every new car listing above $500 carries demountable 
rims as a part of the equipment included in the price. This situation, 
too, was not brought about in a minute. In the beginning there were 
hundreds of different forms and kinds, none of which would fit any 
other wheel, many of them requiring a special tire which would not 
fit anything else. By concerted action, this situation has now been 
cleared up, although it is not yet settled. There are now less than a 
dozen forms of demountable rim in wide use in this country, each 
of these available in any commercial size of tire. Just as soon as the 
tire situation has been closed up along the lines mentioned above. 



rims also will be standardized and a large number of the present 
types and sizes eliminated. As pointed out previously, the advantage 
of a demountable rim is that it allows of the complete removal of the 
damaged tire and rim, and its replacement by a new ready-inflated 
tire on its rim. This is the work of seconds only. 

As was mentioned on page 80, one of the big reasons for the fast 
growing popularity of wire wheels is the fact that they are quick 
demountables in themselves, the complete wire wheel with its tire 
being replaced by a new one with tire ready inflated. This necessi¬ 
tates the carrying of at least five wheels, four under the car and one 




244 



GASOLINE AUTOMOBILES 


85 


on it, but as the five will weigh less than the usual four wood wheels, 
this does not add to the weight. The change of wheels can be made 
more quickly than the change of demountable rims, in fact, on some 
racing cars it is made in less than a minute, one notable change 
having been made in 45 seconds. 

Steering Gears. No more serious accident can befall an auto¬ 
mobile than for the driver to lose control over its direction of travel. 
For this reason the design and construction of a steering gear is a sub¬ 
ject of the greatest importance. 

Wheel Steering . Steering by a hand wheel, instead of by a 
lever, has become almost universal within the last few years of 
automobile development, the only innovation in this period being 
the growing tendency in the United States, and in other countries 
where vehicles pass to the right, to place the driver and the steering 
wheel at the left, that he may better observe passing vehicles. 

This tendency has grown so rapidly that it can almost be put 
dow T n as a feature rather than a tendency of the 1916 cars. While 
there were but 10 per cent of the American makers favorable to this 
in 1912, the following year it had risen to 30 per cent, in 1914 to 66 
per cent, in 1915 to 87, and for 1916 to 91. 

Lever Steering. Except in inside-driven electric automobiles 
lever steering is now practically obsolete, chiefly because it does not 
provide sufficient control over an automobile moving at high speed. 
Even on electric cars it seems to be losing ground rapidly, as a con¬ 
siderable number of the newest electrics are equipped with wheel 
steer, similar to gasoline cars. It would not be surprising to see lever 
steering disappear entirely before 1917. 

Irreversibility . This is an important consideration in the design 
of a steering gear, its object being to prevent the transmission of 
road shocks from the wheels to the hand of the operator, in such a 
way that they will quickly cause fatigue and perhaps cause - the 
control to be jerked away from the driver for a long enough period 
to cause trouble. As commonly designed, automobile steering gears 
are so made that the steering wheel operates through a worm-and- 
sector, or a screw-and-nut, in such a manner that the movement 
can be transmitted only in one direction. 

Referring to Fig. 59, this shows the entire steering system and 
how it works, in a very simple manner. By turning the hand wheel A 


245 


86 


GASOLINE AUTOMOBILES 


in any direction, as, say, toward the left, the worm turns the sector 
in such a manner that the lever E swings backward, pulling the rod G 
and with it the steering knuckle iff, which turns upon its pivot, so 
that the wheel goes forward, relative to its previous position, and 
points toward the left, the direction in which the hand wheel was 
turned. The cross connecting rod behind the axle forces the other 
knuckle to turn in a similar manner, so both wheels point to the left. 

ELECTRIC LIGHTING AND STARTING 

For automobile headlights, side lamps, tail lamps, and general 
illumination, electric lighting has practically replaced the at-one-time- 
popular acetylene gas systems, which required either a large amount 
of attention, if acetylene generators were used, or a frequency of 
replacement, if gas tanks were used, that were causes of much annoy¬ 
ance and trouble. 

In the best electric lighting systems the current is supplied by 
dynamos driven constantly by the engine, with a storage battery to 
supply current when the motor is stopped. The system thus is 
completely self-contained and illumination is always on tap, regard¬ 
less of any source of supply outside of the car. The facility with 
which electric lights can be switched on and off, avoiding the troubles 
of lighting up in a wind, which are so unpleasant with gas or oil 
lamps, is not the least of the advantages of electric lighting. 

Two=Unit System Gaining. For electric lighting and starting 
work, the two-unit system is gaining fast, although the single unit 
still has the greater number of individual cars to its credit. By this 
reference is had to the separate generator and starting motor as 
compared with the one combination generator-starter. 

In both forms, the battery is an essential unit, for the current 
is stored in it and used from it, rather than used directly from the 

generator. The general arrangement is such that a part of the battery 

supplies the lighting, horn, and other current demands at a low volt¬ 
age, while for starting two or more sections of the battery are used 
as one to give a doubled or greatly increased voltage for the harder 
work of starting. 

This is not an essential for there are low voltage starting motors, 
and in any case it is simply a method of wiring. 

In general, the single wire or grounded return system is used on a 


GASOLINE AUTOMOBILES 


87 


majority of cars. In this, the frame of the car or other metallic parts 
are used for the return path of the electric current. In the two-wire 
system, a separate set of wires is used solely for the return current. 
The simplicity of the former from every standpoint manufacturer, 
user, repairman, and others—has brought about its general adoption, 
and this in turn is leading rapidly toward standardization of wires 
and wiring, as well as terminals, fuses, junction boxes, and other 
wiring essentials. 

Improvement of Mechanical Parts. A mechanical part of the 
starting system which has been improved greatly is the starting pinion 
and the method of meshing this. The Bendix gear has been quite 
generally adopted and a few manufacturers have gone even farther 
and provided a form of pinion and gear tooth which assists in meshing 
on the one hand and unmeshing on the other. A still further and 
very welcome improvement is the use of an electrical gear shift with 
a solenoid to draw the starting pinion into mesh, so that the driver 
has simply to press a button. On the less expensive cars, however, 
the driver must make both the mechanical shift of the gears by hand 
or foot, and the electrical 
connection. 

The very general use of 
electric lighting and starting 
may be noted in the simple 
statement that 98.8 per cent 
of the cars for 1916 are so 
equipped. The cars not in¬ 
cluded in this are the Ford, 

Vixen, and Woods Mobilette, 
of which the Ford is now to be 
had with electric lighting. 

The rapid strides which the 
use of electric current has made are shown in the statement that in 19 
but 2 per cent of the cars were so equipped and in 1913 but 37 per 
cent. But by comparison with the very efficient and simple appara¬ 
tus of today, that of the early days is seen to have been crude and 

added to the car as an afterthought. 

Control Systems. As might be expected, the addition of elec¬ 
tricity to the motorcar in its many forms, notably lighting and 



Fig. 60. Arrangement of the Electrical Control Group 
on the Steering Post of Overland Cars 




88 


GASOLINE AUTOMOBILES 


starting, has not only added a large number of parts to the control 
system but, in addition, has brought about a large number of changes. 
For one thing, the modern tendency toward centralization of the 
control as well as the addition of instrument boards, has brought 
the whole group right up close to the driver instead of scattered all 
over the dash, front seat, and under the hood, as was formerly the case. 

One marked tendency is to place a considerable quantity of the 
control units on the steering wheel or post. As an example of this, 
Fig. 60 shows the side of the steering post on the Overland car. Here, 
m one small panel less than six inches long, are to be found the 
starting button, the warning signal, the ignition switch, three light- 



Fig. 61. Complete Control Panel on the Dashboard of the Pierce-Arrow Car 
Courtesy of Pierce-Arrow Motor Car Company, Buffalo, New York 


ing switches, and the lock by means of which all of these devices are 
positively controlled. The latter really should be considered as a 
part of the control system, for it controls the possession of the car by 
preventing theft. 

An equally marked tendency is the grouping on dash or instru¬ 
ment board, a particularly pleasing example of which is shown in 
Fig. 61. Here all the control units, not ordinarily placed on the 
steering wheel, are to be found in one neat panel in the center of the 
dashboard, which is finished off with a pair of compartments on either 
side, both fitted with locks. This panel, too, shows a remarkably 
complete control system, including as it does oil and gasoline 







GASOLINE AUTOMOBILES 


89 


gages, voltmeter, separate odometer, speedometer and clock usually 
grouped in one, starting button, electric lighting buttons, kick 
switch for ignition with key for locking the same, and others, all 
illuminated so that each one is visible to the driver at night. 

As mentioned previously, one change in the body form has been 
the addition of the instrument board, so-called from its function of 
bringing up close to the driver, all the instruments needed for the 
control of the car. In many cars, the control group just shown on 
the Pierce dash, and on the Overland steering post, with other units, 
if any, are placed close together at the end of the instrument board 
nearer the driver—at the right-hand end with right control, and at 
the left-hand end with the newer left-hand control. This board, too, 
is carried so close to the driver that he can reach it or any part of it 
by leaning forward a very short distance—not enough to endanger 
his control of the car. 

BODIES 

As the portion of an automobile that provides the accommoda¬ 
tion for the passengers, or that contains the merchandise to be 
hauled, as the case may be, the body is a most important element, 
well worthy of all of the study that can be expended upon its problems. 

As is suggested in a preceding paragraph, the motor vehicle, 
for its fullest usefulness, requires bodies fundamentally designed for 
it rather than adapted to it from other constructions. Only by 
growing recognition and application of this fact has it been possible 
for the automobile of all types—pleasure and commercial to 
develop to its present practical status. 

Pleasure Bodies. Under this heading are usually grouped all 
types of open and closed bodies used for the conveyance of passengers, 
with the exception of omnibus bodies, which ordinarily are mounted 
on truck chassis and used for the conveyance of passengers on urban 
and suburban routes. The slight confusion in terms that results, 
involving, for example, the classification of such public service 
vehicles as the taxicabs of modern cities under the heading of “pleas¬ 
ure cars”, is an incongruity that perhaps has already been sufficiently 
dismissed with the statement previously made, that pleasure is a 
high type of utility. 

Open and Enclosed Bodies. These embrace, in their standard 
forms, the various established types of the roadster—for carrying 


249 




GASOLINE AUTOMOBILES 


Fig. 63. Kissel Four-Passenger Two-Door Body, Showing Pleasing Streamlines 
Courtesy of Kissel Motor Car Company, Hartford, Wisconsin 

usually only two persons, though sometimes provision is made for 
another at the rear or one side; the touring car, for four to seven 
passengers; the coupe, for from two to four passengers; the limousine. 


Fig. 62. Oakland Roadster Body, Showing Streamline Form and Clean Running Board 
Courtesy of Oakland Motor Car Company, Pontiac, Michigan 


250 







GASOLINE AUTOMOBILES 91 

for seven passengers and sometimes more; the landaulet, similar to the 
limousine, except that part of the top is capable of folding; and the 
berline, similar to the limousine, except that the driver s seat is 
completely enclosed. Still later forms which might be considered as 


Fig. 64. Typical Seven-Passenger Touring Car, 1917 Model 
Courtesy of Locomobile Company of America, Bridgeport, Conn. 

distinct from these are the eoupelet or landau, as the enclosed 
two- or three-passenger roadster which can be converted to an open 
car by dropping the top, is called; the sedan, in which the whole 
enclosed interior is in one compartment, as distinguished from the 


Fig. 65. Exaggerated “Streamline” Body, the Marmon “Wasp” 

Courtesy of Nordyke-Marmon Company, Indianapolis, Indiana 

limousine, landaulet, or berline (usually this form has individual 
seats which are movable); the racing roadster, differing from the 
usual roadster in that it has practically no body, a pair of bucket 
seats being superimposed upon the chassis (at most this form on y 


251 







92 


GASOLINE AUTOMOBILES 


approximates a roadster in that it has some form of seats); the 
vestibule tourist, which differs from the usual tourist in that there 
is a passageway between the two individual front seats, wide enough 
for use (in this form, the front seats are often made to swivel so that 
the passenger in the odd front seat may turn around and face the 
other passengers); and the various convertible and detachable 
forms. The latter have of course been brought into being by the 
all-year-round use of the car, instead of putting it up for the winter, 
as formerly. In that sense, these types and the coupelet or landau 
may be considered as developments of former touring-car and road¬ 
ster bodies. 

In Fig. 62 is presented a modern roadster, a vehicle for two, 
although many of these have so wide a front seat that they accommo¬ 
date three. In several cars, in order to make this possible, the driver’s 
seat has been set some 6 or 8 inches forward of the others, which 
then can be widened out a few inches where the two meet. In Fig. 
63 is presented a modern four-passenger car with individual seats and 
a vestibule between the two front ones, as just mentioned. Fig. 64 
shows a larger five- or six-passenger touring car, which, with folding 
seats for two, could easily accommodate seven or eight. 

Fore Doors. Doors similar to those long used beside the rear 
seats, but applied between the sides of the front seats and the dash¬ 
board, are now universal on modern open cars. Besides making for 
warmth in winter and the exclusion of dust in the summer, they 
also adapt themselves especially well to incorporation in the lines 
of popular recent body designs of more or less streamline form. 

Streamline Forms. These forms, which aviation research has 
proved to be the correct ones for bodies to move through air with a 
minimum resistance and disturbance, have been more or less success¬ 
fully applied to many automobiles, in the shape of torpedo and 
similar bodies, of one design and another, in which it has been sought 
to incorporate, as fully as conditions will permit, certain of the more 
marked advantages of these forms. 

An extreme but quite successful application of the streamline 
form to an automobile body is illustrated in Fig. 65, which is a picture 
of the Marmon “Wasp”, and which achieved, with very moderate 
power, a most enviable record in various races and competitions 
in the United States. 


GASOLINE AUTOMOBILES 


93 


The particular effect of a streamline form of this type, with its 
long tapering rear, is to secure a definite propelling pressure resulting 
from the elastic masses of parted air springing together again upon 
the tapered rear, and thus returning a portion of the energy expended 
in overcoming the head resistance. 

In the case of the automobile illustrated in Fig. 65, it is estimated 
that there is a saving, at high speeds, of as much as 30 horsepower. 

The more practical advantage of the streamline form, from the 
standpoint of the average user who is not directly interested in the 
phenomena of high resistances at high speeds, inheres in the fact 
that the same conditions that reduce air resistance also reduce air 
disturbance, and so avoid stirring up as much dust as is raised by 
ordinary bodies. 

By referring back to Fig. 62 an excellent idea of the modern 
streamline body can be had, in addition to which the speed possi¬ 
bilities and power savings of this form should be pointed out. This 
particular car has a wheelbase of 112 inches, yet its motor, with a bore 
of but 3| inches and rated at only 19.6 horsepower, will propel the 
car at speed closely approximating a mile a minute. A few years ago, 
no motors were built within 1 inch of this size—that is, 4J inches 
was considered the smallest size which it was practicable to build. 

This model and that shown in Fig. 63 in particular, show to what 
extent fore doors have blended into the streamline body to give an 
unbroken line from front to rear, as well as a neat and pleasing 
appearance. In the latter, attention is called to another modern 
simplification, namely the elimination of one pair of doors. In this 
figure, it will be noted that the car has but two doors, instead of the 
more usual four. Besides the good points previously dwelt upon, this 
construction should make a stronger body, for the side members are 
weakened in but one place instead of two. 

Tire , Battery, and Tool Storage. The problem of storing away 
the various impedimenta that a motorist must carry is one of those 
that for long was dismissed with scant attention, because of the 
greater importance of more serious problems with which the auto¬ 
mobile engineer was faced. Now, however, there is a commendable 
tendency to provide in a practical and workmanlike manner for the 
stowing of extra tires, batteries for ignition or illumination, and such 
tools as it is well to have always with the vehicle. 


94 


GASOLINE AUTOMOBILES 


Recent progress in the matter of tires has made the tire-storage 
problem evolve into really a wheel-storage problem, since most 



Fig. 66. Thirty-Passenger Motor Omnibus 
This Photograph Protected by International Copyright 



Fig. 67. Pierce 5-Ton Motor Truck with Dumping Body 


motorists, who know what is what, will not nowadays use a car with¬ 
out demountable wheels or rims, which enable replacements to be 
made on the road and repairs at home. 


254 



























GASOLINE AUTOMOBILES 


95 


One much-favored way of carrying one or two extra tires is to 
strap them to brackets on the running board on the driver’s side. 
Another is to carry them in brackets at the rear, an arrangement 
nicely adapted to runabouts, but not so convenient if it is also desired 
to carry a trunk at the back of the machine. With limousines and 
coupes, it is not unusual to place the tires on the roof. 

Battery and toolboxes have in times past encumbered the run¬ 
ning board, and do still to a great extent, but the policy of placing them 
completely inside the body, or, as in a few instances that have 
appeared recently, in pockets built into the apron between the run¬ 
ning board and the frame sill, has many features to recommend it. 

This too, is a feature which has seen much exploitation and 
development since the streamline form of body began to appear. It 



Fig. 68. Seagrave Motor Pumping Engine—Capacity 1000 Gallons a Minute 


was impossible to have a true streamline so long as a miscellaneous 
collection of tool and battery boxes cluttered up the running board, 
consequently designers were obliged to find less conspicuous posi¬ 
tions for batteries, tools, etc. 

For one thing, the modern car is more dependable, so that there 
does not exist the need for the use of tools, spare parts, etc., that was 
ever-present but a few years ago. Consequently body designers 
have been able to take them from the convenient places without 
calling forth protests from the owners and drivers. 

Tires, however, have not had the attention they should have and 
it is still common practice to carry them about any place where there 
is room for them and a method of fastening. As light, heat, air, dirt 
practically everything but plain water-are injurious to rubber tires 
and even water can damage the fabric, they cannot have too much 






90 GASOLINE AUTOMOBILES 

care. Bodies should have a compartment built into the rear end 
where one or two spare tires could be carried, with suitable fastenings 
to hold them firmly in place, these too, large enough and arranged so 
as to take wire wheels if necessary. 

Commercial Bodies. Automobile bodies for commercial uses 
range from the simplicity of the flat platform truck to the expensive 
and elaborate closed bodies used for automobile omnibuses. 

An exceptionally capacious and well-designed type of motor 
omnibus is that illustrated in Fig. 66, which illustrates a type of 
vehicle capable of carrying thirty passengers, that is in general 
and successful use on the streets of Paris. 

In Fig. 67 is shown a typical American motor truck of 5 tons 
capacity, a vehicle which has been unusually successful both at home 



Fig. 69. French Military Truck for Carrying Cannon 
This Photograph Protected by International Copyright 


and abroad, a number of very large orders for this make having been 
placed by foreign armies. The vehicle is shown with a wood dump 
body, as used by a western city. This [calls attention to two things, 
first that much of the progress of recent years in motor truck con¬ 
struction has centered around body materials. Pressed steel is now 
used to a very large extent, modern welding processes making it 
possible to construct entire and very intricate forms of this permanent 
material. 

The other point is that no one use of commercial vehicles has 
grown more quickly than that of the various city departments. 
Makers have catered to this, so that special vehicles have been 
forthcoming as soon as a demand was apparent. In this line of 


256 




GASOLINE AUTOMOBILES 


97 


municipal vehicles, reference might be made to Board of Health 
and Public Works cars; to ambulances and supply wagons for hospi¬ 
tals, etc.; to police patrols; and to special designs for various other 
uses. A notable example which points out the progress in the latter 
field is seen in Fig. 68, which presents a pumping engine with a 
capacity of 1000 gallons of water an hour, powered with a six-cylinder 
100-horsepower motor, and capable of speeds up to 45 miles an hour. 
This is shown being tested-out on the New York City water front. 

A most unique motor vehicle is that illustrated in Fig. 69. This 
machine, of a type of which a number have been manufactured for 
the French army, is mounted with a quick-firing gun that can be 
got into almost instant action, for use in line-of-battle, for harassing 
small bodies of troops, or for bringing down aeroplanes. In marked 
contrast to the generality of heavy automobiles, it is driven by a 
very high-power motor, is carried on pneumatic tires—double on 
the rear wheels—and is capable of very high speed. 

Interchangeable Bodies. Particularly from the users of small 
delivery wagons—the tradespeople in the smaller cities and towns 
there is commencing to be heard a demand for interchangeable bod¬ 
ies, permitting the fise of a single chassis for pleasure use when 
desired, and for commercial or delivery service when required. 

The many different automobiles on the market are built on a 
much smaller number of chassis, and there are even prominent 
manufacturers who devote their entire activities to the construction 
of one type of chassis, to which they fit a variety of bodies. The 
result is that the interchangeable body is more generally available 
than is commonly supposed. That there is a big future before it is 
evident from the most casual analysis of needs and demand, and 
manufacturers are finding that it pays to cater to this demand by 
bending every effort to simplify and facilitate the interchange of the 
different body types. 


257 





CHALMERS SIX-40 MOTOR WITH OVERHEAD CAMSHAFT 

Courtesy of Chalmers Motor Company, Detroit, Michigan 



SECTION OF BUICK, SIX-CYLINDER MOTOR 

Compare with the motor shown above. Both have the valves in the head but in the Chalmers 
the camshaft is overhead, and in the Buick it is alongside the crankshaft. 

Courtesy of Buick Motor Company, Flint, Michigan 


258 


































































GASOLINE AUTOMOBILES 

PART II 


VALVE GEARS 

Probably the most important thing about a four-cycle gaso¬ 
line engine is the valve, or more correctly, are the valves, for the 
usual number is two per cylinder. The opening and closing of these 
control the functions of the engine, for if the valve does not open 
and allow a charge of gas to enter, how can the piston compress, 
and the ignition system fire, a charge? Similarly, if the exhaust 
valve is not opened and the burned gases allowed to escape, they 
will mingle with and dilute the fresh, incoming charge, possibly to 
the extent of making the latter into a non-combustible gas. This 
is purposely stated in this way because both methods mentioned 
have been utilized for governing the engine speed, although not to 
any great extent in automobile work. 

CAMS 

Friction. Granting the necessity for proper means to regulate 
the inflow and outgo of the charge and consequent products of 
combustion, as exemplified by the valves, the next most important 
part is the one which controls the movement of the valve, and is, 
therefore, essential to the success of the latter. This is what is known 
as a cam and in the usual case amounts to an extension of or pro¬ 
jection from the so-called camshaft. Inasmuch as the valve func¬ 
tions only come into play upon every other stroke of the crankshaft, 
this camshaft is gear-driven from the crankshaft, so as to rotate at 
half the speed of the latter. This is very simply effected by having 
the cam gear twice as large as the crankshaft gear, that is, with 
twice as many teeth. As the same valve is never used for both the 
inlet and the exhaust, so the cams are seldom made to do more than 
the one thing, namely, operate one of the valves. From this has 
grown the custom of referring to them according to the function of 
the valve which they operate inlet cam, exhaust cam, etc. 



100 


GASOLINE AUTOMOBILES 


TABLE I * 


Timing Regulation of a Number of Prominent French Motors 


Nos. 


Lead 
of Ex¬ 
haust 
Open¬ 
ing 

Lag of 
Inlet 
Clos¬ 
ing 

Ignit. 

Ad¬ 

vance 

Lag of 
Exh. 
Clos¬ 
ing. 

Lag of 
Inlet 
Open¬ 
ing 

Rela¬ 
tion of 
Conn. 
Rod to 
Radius 
Crank 

R.p.m. 
at Full 
Power 

1 

Ours. 

55° 

20 b 

var. 

0° 

15° 

4.76 

1 000 

2 

Charron—20/30 h.p., 1908. 

44° 

0° 

__ 

0° 

1° 

4.55 

1 100 

3 

Rossel—40 h.p., 4 cylinders. 

38° 

23° 

— 

0° 

2° 

4.29 

1 100 

4 

Gregoire—10/14 h.p., 4 cylinders, 









1908. 

53° 

0° 

•—. 

0° 

5° 

4.18 

1 200 

5 

Motobloc—24 h.p., 100/120, 









1908. 

45° 

10° 

— 

5° 

10° 

4.75 

1 200 

6 

Panhard-Levassor. 

45° 

40° 

— 

0° 

0° 

4.5 

1 200 

7 

Hotchkiss—4 cylinders, 95/100. . 

44° 

33° 

— 

10° 

17° 

4.27 

1 300 

8 

Cottin-Desgouttes—18/22 h.p.. . 

46° 

30° 

38° 

8° 

15° 

4.15 

1 300 

9 

Brouhot—12 h.p., 4 cylinders, 









75/110. 

45° 

45° 

30° 

0° 

20° 

5 

1 300 

10 

Cornilleau -Ste. - Beuve — 20/30 









h.p., 1908...... 

56° 

20° 

43° 

6° 

20° 

4.62 

1 300 

11 

Mutel—40 h.p., 1908. 

62° 

21° 

var. 

28° 

26° 

4.4 

1 300 

12 

Berliet—22 h.p., 1908. 

48° 

38° 

— 

9° 

17° 

4.5 

1 300 

13 

Peugeot (Paris) —18/24 h.p., 









1908. 

58° 

18° 

38° 

0° 

10° 

4.76 

1 300 

14 

Labor—20/30 h.p. 

51°20' 

0° 

var. 

0° 

0° 

4.18 


15 

Luc Court. 

45° 

0° 


15° 

30° 

4 25 


16 

Brasier. 

45° 

25° 

34° 

0° 

7° 

4.5 

1 350 

17 

Peugeot ( Beaulieu ) . 

51°30' 

58° 

31° 

20° 

15° 

4.78 

1 400 

18 

Aster—9 h.p., 105/120 . 

40° 

40° 

var. 

0° 

0° 

4.3 

1 400 

19 

Rochet-Schneider—24 h.p., 100/- 









120. 

40° 

20° 

20° 

0° 

20° 

4.75 

1 400 

20 

De Dion-Bouton—12 h.p., 4 cylin¬ 









ders, 1908 . 

45° 

45° 

30° 

0° 

0° 

4.7 

1 400 

21 

Eudelin. 

36° 

20° 

var. 

4° 

8° 

4.3 

1 450 

22 

Farcot—14 h.p., 80/100. 

36° 

10° 

— 

2° 

6° 

4 

1 500 

23 

Chenard-W alcker. 

36° 

36° 

— 

0° 

0° 

5.25 

1 500 

24 

Darracq—10/12 h.p., 100/120.. . 

48° 

30° 

21° 

0° 

0° 

4.5 

1 500 

25 

Aries—14/18 h.p. 

58° 

44° 

20° 

13° 

18° 

4.91 

1 500 

26 

Vinot-Deguingand — 12/16 h.p., 









80/110. 

30° 

15° 

27° 

0° 

15° 

4.54 

1 500 

27 

Sultan—9/12 h.p., 4 cylinders, 









75/110. 

58° 

42° 

32° 

14° 

22° 

4.55 

1 600 

28 

Renault—8 h.p., 2 cylinders. . . . 

32° 

26° 

33°30' 

10° 

23°30' 

4.33 

1 600 

29 

Unic—20 h.p., 75/110. 

53° 

40° 

30° 

10° 

34° 

4.5 

1 650 

30 

Sizaire et Naudin—15 h.p., 120/- 









110. 

44° 

37° 

var. 

0° 

15° 

5.25 

1 700 

31 

Larrad Device. 

52° 

17° 

_ 

22° 

17° 




Average. 

46°20' 

26°15' 

- - ; 

5°40' | 

8°6' 




* The motors are arranged in the order of their increasing speeds. The angles are figured 
in degrees, counting from the nearest dead center. “Var.” means that the point of ignition may 
be advanced or retarded by the driver. 


In laying out or designing a set of cams for a gasoline engine, 
such as is used on an automobile, it is first necessary to decide upon 
the exact cycle upon which to operate the engine. By this is meant 
the exact length of time, as referred to the stroke, in which the valve 
action will take place. Upon this subject, designers all over the 
world differ, and no wonder, as this cycle can but be judged by 
results, for it is impossible to watch it as it transpires. Deductions 
differ, therefore, as to what happens, and consequently, as to the 
effect of various angles of beginning and ending of the valve actions. 


260 















































GASOLINE AUTOMOBILES 


101 


TABLE II 

Timing Regulation on a Number of Prominent American Motors 


Nos. 

H * 

Lag of 
Inlet 
Opening 

Lag of 
Inlet 
Closing 

Lead of 
Exhaust 
Opening 

Lag of 
Exhaust 
Closing 

1 

Abbott* 34—40 . 

11° 30' 

44° 12' 

45° 48' 

11° 30' 

2 

A hhott, 44/50 . 

17° 53' 

29° 25' 

42° 36' 

8° 20' 

3 

Abbott Belle Isle . 

10° 00' 

20° 00' 

40° 00' 

2° 30' 

4 

Allen 40 . 

15° 00' 

40° 00' 

45° 00' 

10° 00' 

5 

Cadillac 1914. 

14° 20' 

38° 26' 

31° 34' 

17° 00'* 

6 

Camernn 1914. 

5° 00' 

20° 00' 

50° 00' 

10° 00' 

7 

Cnrbit.t D, E, a.nd E. 

11° 00' 

35° 00' 

45° 00' 

3° 00' 

8 

Chalmers. 

12° 00' 

33° 00' 

55° 00' 

12° 00' 

9 

Crescent ... . 

20° 00' 

45° 00' 

55° 00' 

15° 00' 

10 

11 

Chandler Six .. 

14° 00' 

39° 00' 

49° 30' 

12° 00' 

Crane 4 . 

35° 00' 

50° 00' 

10° 00' 

12 

Cnrreja. ... . 

10° 00' 

35° 00' 

44° 00' 

5° 00' 

13 

Chevrolet, C . 

13° 00' 

49° 00' 

47° 00' 

9° 00' 

14 

Ca.se 40 . . 

13° 00' 

30° 00' 

50° 00' 

13° 00' 

15 

Cunningham. 

15° 00' 

15° 00' 

40° 00' 

12° 00' 

16 

Tie Snt.n Six . 

10° 00' 

25° 00' 

38° 00' 

8° 00' 

17 

18 

19 

20 
21 
22 

23 

24 

Franklin V— 4 . 

8° 00' 

33° 00' 

51° 30' 

17° 00' 

Oreat* Southern. 

14° 00' 

25° 00' 

35° 00' 

10° 00' 


5° 00' 

35° 00' 

47° 00' 

2° 00'f 

Howard b—T) . 

10° 00' 

28° 00' 

40° 00' 

2° 30' 

Hiiprnobilo 32 . . 

21° 00' 

28° 00' 

46° 00' 

16° 00' 

Jackson Olympic, Majestic, and Sultanic 
jpffp^y Qb and 4—93. 

15° 00' 
18° 00' 

38° 00' 
46° 00' 

45° 00' 
47° 00' . 

10° 00' 

15° 00' 

TC i n g P . 

9° 44' 

30° 38' 

32° 10' 

5° 00' 

25 

26 

27 

28 

29 

30 

31 

32 

33 

34 

35 

36 

37 

38 

39 

40 

41 

42 

43 

44 

45 

46 

47 

48 

49 

50 

51 

52 

53 

K ri t, TVT . 

12° 00' 

28° 00' 

39° 00' 

2° 00' 

Pewi*^ Six .. 

15° 00' 

30° 00' 

45° 00' 

5° 00' 


Dead Center 

46° 22' 

50° 52' 

16° 27' 

lVTnFprla.n b—T*. 

10° 00' 

36° 00' 

43° 30' 

10° 00' 


5° 00' 

40° 00' 

35° 00' 

Dead Center 

lYTaxwell 4—25. t . 

6° 00' 

32° 00' 

43° 00' 

6° 00' 


10° 00' 

28° 00' 

40° 00' 

2° 30' 


14° 00' 

24° 00' 

31° 00' 

21° 00' 

Marathon Winner, Runner, Champion. . 

12° 00' 

8° 00' 

45° 00' 
40° 00' 

46° 00' 
45° 00' 

7° 00' 

10° 00' 


6° 00' 

40° 00' 

45° 00' 

5° 00'$ 


15° 00' 

38° 00' 

45° 00' 

10° 00' 


9° 40' 

32° 25' 

40° 30' 

12° 00' 


9° 40' 

32° 30' 

41° 50' 

11° 40' 


6° 00' 

40° 00' 

45° 00' 

5° 00' 


15° 00' 

38° 00' 

45° 00' 

10° 00' 

Pathfinder 4. 

11° 30' 

44° 12' 

45° 48' 

11° 30' 

Feif-hfindpr Pier and Pit,tie Six. 

10° 00' 

28° 00' 

40° 00' 

2° 30' 

Pratt 50 . 

12° 00' 

45° 00' 

45° 00' 

10° 00' 


18° 00' 

36° 00' 

53° 30' 

14° 00' 


15° 00' 

30° 00' 

45° 00' 

10° 00' 

S & M . 

10° 00' 

28° 00' 

40° 00' 

2° 30' 


13° 00' 

26° 30' 

48° 30' 

7° 30' 


13° 10' 

34° 40' 

57° 30' 

15° 40' 


10° 20' 

31° 40' 

54° 20' 

7° 50' 


5° 00' 

45° 00' 

55° 00' 

5 U 00' 


10° 00' 

28° 00' 

40° 00' 

2° 30' 


3° 00' 

40° 00' 

43° 00' 

3° 00' 

Yelie 9-45, 6-40, 9-5, 9-4, 9-2, 6-5, anc 

0 4 . 

7° 00' 

36° 00' 

43° 00' 

12° 00' 

54 

55 

56 

Velie il 35 . 

5° 00' 

31° 00' 

39° 00' 

13° 00' 


15° 00' 

30° 00' 

45° 00' 

10° 00' 


10° 00' 

25° 00' 

38° 00' 

8° 00' 

Average. 

10° 48' 

35° 7' 

50° 10' 

9° 20' 


* Some Cadillacs have the inlet opening at 4° 20' past the top center and the exhaust 

closing 7° 00' past. . _ 

f The Haynes 28 has the exhaust opening 37° 00' before the lower center instead of 47 00 . 

J Norwalk 6-D has the inlet opening at 8° 00' instead of 6° 00', and the exhaust closing 
on the upper dead center instead of at 5° 00 past. 


Tables of Valve Settings. Table I, showing the valve settings 
used by the foremost French car designers, is here given as a basis 








































































102 


GASOLINE AUTOMOBILES 


of comparison with the valve data of American types, Table II. As 
Table II gives the valve timing for American cars as produced in 
1913 and 1914, while Table I was compiled in 1908, a comparison 
indicates in a measure the advance in the past five or six years. In 
studying these tables, it should be borne in mind that all angles are 
spoken of in terms of the crankshaft, and are usually referred to the 
two dead centers, commonly spoken of as the upper dead center and 
the lower dead center. 

Referring to Tables I and II, it will be noted that in so far as 
maximum openings were concerned there has been little change. 
The earliest exhaust opening of 1908 was Mutel at 62°; the earliest 
American exhaust opening of the present is Simplex 50 at 57° 30'. 
The former closed at 28°, while the latter closed at 15° 40', thus 
giving the French motor a total exhaust opening of 270°, while the 
American has but 253° 10'. Simplex is not a representative American 
car, however, this being a special model with racing characteristics, 
and is built only to order. Crescent and Reo are the real leaders. 

With reference to inlet valves, the situation is somewhat similar, 
the largest foreign lag in opening being Unic with 34°, while the 
largest American opening lag is Hupmobile with 21°. In closing, 
the highest figure reached by the foreign product is 58° by Peugeot, 
and on this side, 49° by Chevrolet. The former shows also the 
greatest total 254°, but the largest American total is that of Crescent 
with 245°. 

These, however, represent the extreme cases, and the averages 
tell a different story. The average foreign inlet opening (total) in 
1908 was 232°, while the average American inlet opening is now 
239.3°. Similarly, with the exhaust total opening, the average 
foreign figure then was 214.5°, the average American figure is now 
226.2°, 

It is unfortunate that the speed at full power output of the 
American motors is not available, also, as that would allow an even 
more interesting comparison of the two tables. In Table I, it will 
be noted that the motors are arranged in the order of their maximum 
speeds. Were the American speed figures available, it would show 
for one thing whether speeds of today are, as claimed, so much 
higher than formerly, and also, what is more to the point, what valve 
setting gives the highest speed. Referring back to Table I, it will be 


262 



GASOLINE AUTOMOBILES 


103 


seen that Unic with the greatest lag of inlet opening and greatest 
total inlet opening is next to the highest in speed, whereas the others 
having high lag figures are all down among the moderate speeds. 

Now, if the average of the numerous examples of good practice 
be taken, it is not a hard matter to explain the form of the cam and 
its derivation. The height of the upper surface of the highest part 
of the cam above the surface upon which the valve-actuating device 


Ar>gl* from Biagr en) 



normally rests determines the lift of the valve, which is the name 
given to the amount it is opened or lifted. This is not really the lift 
of the valve because of the fact that in all valve-operating systems 
there is a certain amount of clearance between the lower end of the 
valve stem and the upper end of the valve lifter mechanism. This 
clearance must be taken up by the cam before the valve itself is 
actually lifted, so, to obtain the true lift, the amount of the clearance 
is subtracted from the lift as determined by the cam height. Know- 















104 


GASOLINE AUTOMOBILES 


ing this, designers usually predetermine the clearance and allow 
for it in the height of the cams. 

Cam Design. In order to lay out a set of cams, not only 
must the cycle be fixed, but the clearance as well. Fig. 70 
shows the way to go about this; the size 
of the shaft is simply determined, and if 
other means fail, the empirical formula 
may be used: 

Camshaft diameter = .6257) — J" 
in which D is the clear diameter of the 
valve opening in inches. 

Having the camshaft diameter fixed, 
lay it out and about it circumscribe the cam 
thickness. This may be from one-eighth 
of an inch, upon very small, light-weight 
engines, to three-eighths inch on larger and 
heavier motors. Around this, in turn, 
describe another circle, distant from the 
cam surface a distance equal to the clear¬ 
ance. A fourth circle representing the 
83 E3 p height is shown only partly complete. 

*1 ^551 From the cycle previously determined 

upon, the total angle of inlet valve opening, 
for instance, is found by simple addition 
and subtraction; thus, if the inlet is to open 
10 degrees past the upper center and close 
20 degrees past the lower center, this makes 
the valve remain open a total of 190 degrees 
upon the crankshaft. As the camshaft turns 
but half as fast and, therefore, but half as 
far in the same length of time, for the cam 
this angle will be halved, or 95 degrees. 
Proceed to lay out half of this, or 47§ degrees, 
on each side of the vertical center line. A 
line forming this angle with the center line 
will intersect the line representing the clearance in a point. Through 
this point draw a line which will be tangent to the circle represent¬ 
ing the surface of the cam, and prolong it upward to meet the 



Fig. 71. Complete Valve 
Motion with Roller Pusn Rod 
Courtesy of Locomobile Company 
of America, Bridgeport, 
Connecticut 


264 







































GASOLINE AUTOMOBILES 


105 


upper circle. Drawing in a round corner completes the cam layout. 
By sketching in the cam roller the progression is shown. Figs. 
71 and 72 illustrate the complete valve action very well, the former, 
that of the Locomobile Company of America, Bridgeport, Con¬ 
necticut, showing the form in which the 
cam works against a roller in the bottom 
of the push rod, this working upward 
in the push rod guide with a dirt exclud¬ 
ing arrangement at the top. The top 
of the push rod bears against the bottom 
of the valve stem with an adjustable 
hardened screw forming the contact. The 
valve is held down on its seat in the cyl¬ 
inder by means of a strong spring, which 
the upward movement of the push rod 
opposes. The valve is guided in and has 
its bearing in the valve guide, made long 
to give large bearing surface. As the 
Locomobile motor is of the T-head type 
the exhaust and inlet valves are on 
opposite sides of the cylinders and are 
operated by separate camshafts. The 
valve mechanism is completely enclosed. 

The second figure shows the valve 
action used on Haynes cars, made by the 
Haynes Automobile Company, Kokomo, 

Indiana. The difference is in the elim¬ 
ination of the roller at the bottom of the 
push rod, which forms the point of con¬ 
tact with the cam. In this form, a flat 
hardened surface makes the push rod 
more simple and reduces the number of 
parts. It has been said against this form 
that the cam scrapes across the push rod face and thus wears it, 
but in actual use it has been found that the push rod rotates and 
in this way the wear is distributed over the whole flat face, which 
in this construction can be made much larger than can the face of 
the roller. The push rods are of the “mushroom” type and are 



Fig. 72. Complete Valve Motion 
without Roller in Push Rod 
Courtesy of Haynes Automobile 
Company, Kokomo, Indiana 












































106 


GASOLINE AUTOMOBILES 


made of nickel steel. The push rod adjustments are completely 
enclosed but may be readily reached without disturbing any other 
unit. They may be removed and replaced without removing the 
valve springs or valves. 

Neither of these systems is in decided favor, designers being 
about equally divided between them. 

The construction and operation of the cam mechanism is the 
same whether used in connection with an exhaust or an inlet valve, 
as the same line of reasoning and the same method of procedure 



Fig. 73. Straight-Sided or Fig. 74. Lay-Out for Uniform 

Ordinary Cam Acceleration Cam 


in both cases would lead to the same results. It will be noticed in 
Figs. 70 and 73 that the straight sided cam has been chosen to 
illustrate the elements of design. 

It has many times been tried and still more often urged that 
the straight surface of the side of the cam is not conducive to the 
best results, because of the fact that when the first straight portion 
of the cam surface strikes the cam roller it does so with so much 
force that it tends to wear the latter in that direction. As for the 
receding face, it has been urged that the ordinary closing of the 
valve is too slow, and that the straight surface, as shown in Fig. 73, 
can be altered so as to allow of speeding up the downward move- 


266 












GASOLINE AUTOMOBILES 


107 


ment of the valve. This idea works out into a curve, Fig. 74, the 
back of the surface being hollowed out so that as soon as the cam 
roller passes the center it drops vertically, due to the tension of the 
spring. This method has been tried, but without success. 

What Good Modern Practice Shows. A more modern way, 
which is fast becoming universal, is to use straight sides for the cams 
and take advantage of rapid closing in another way, the benefits of 
which more than offset the benefits of the old way, while having no 
corresponding disadvantages. In the ordinary automobile engine 
running at 1000 revolutions per minute, the gases are traveling 
into the cylinder at the rate of 5000 to 6000 feet per minute, and 
traveling out at from 7000 to 10,000 feet per minute. At this tre¬ 
mendous speed, the gas inertia is very high, and experiments go to 
show that the gases by 
means of this inertia will 
continue to force their 
way into the cylinder 
even against the return 
motion of the piston. 

So it is now common 
practice to hold the inlet 
valve open about 30 de¬ 
grees on the upstroke of 
the piston, which results 
in a much larger piston 
charge. The same prac¬ 
tice is carried out with the exhaust, but as the pressure is higher, 
so large an angle is not necessary. These actions take place on 
the back —flat side—of the cam surface, and have given to the high¬ 
speed automobile engine a larger charge and a more complete 
scavenging effect, resulting in more power and speed from the same 
sized cylinder.- 

As proof of this statement, the power curve of an engine of 
but 3|-inch diameter of cylinder is shown in Fig. 75. This size of 
six-cylinder engine would be rated by any formula at about 29 
horsepower at the maximum speed, and a commercially obtainable 
type in this size would doubtless be guaranteed to deliver between 
20 and 25 horsepower. This engine, not built for racing purposes, 



Fig. 75. Power Curve of an American Engine with 
Superior Cams and Balancing 


267 





























108 


GASOLINE AUTOMOBILES 


displays a power curve which continuously rises, a speed at which it 
would turn downward not having been obtainable in the tests. 
This curve shows also that the maximum power obtained was over 
80, which is nearly three times the power of the ordinary engine of 
this same size. This result is ascribable to superior valves and 
superior attention to the valve angles as governed by the cams. 

When it was stated that but two valves per cylinder were ordi¬ 
narily used, with one cam for each, the majority case was spoken of. 
But, as it is a fact that there are other cases which differ from this, 
it would not be fair to close the subject without mentioning them. 
Thus, the most prominent advocate of air cooling in this country 

and the world, the H. H. Franklin 
Manufacturing Company , used three 
valves, and consequently three cams, 
per cylinder. These three were: the 
ordinary inlet; the usual exhaust; 
and the additional auxiliary exhaust. 
By re-designing later, this complica¬ 
tion was avoided and the third valve 
eliminated. 

One Cam per Two Valves In= 
fluences the Shape. A case in which 
the cam does differ is that of the 
use of two overhead valves oper¬ 
ated by a single camshaft, Fig. 76. 
This practice originated with the 
F. I. A. T. Company, which brought 
it out for racing use only, where it was particularly useful in that it 
halved the weight of the camshaft, as well as saved much weight in push 
rods, etc. Later, this was taken up by other firms for regular use, 
although the company which first brought it out has never done so. 
In our own country, the device was adopted by the Pope Toledo 
Company, the Stoddard-Dayton, De Luxe, and others. The work 
of opening the extra valve is done by a spring, i.e., a depression in 
the back of the cam allows a strong spring to pull the push rod down, 
by which process the valve stem is depressed and the valve opened. 

The V-type of motor has made considerable difference in valve 
motions, for one thing bringing into use valves set at an angle with 



Fig. 76. Overhead Valve Motion with 
Followers Working Directly on Valve 
Stems and Having no Push Rods 
Courtesy of Chalmers Motor Company, 
Detroit, Michigan 


268 
















GASOLINE AUTOMOBILES 


109 


the vertical, a practice previously considered very bad because the 
weight of the valve adds to the tendency to wear the valve and seat on 
the low side. In the form shown in Fig. 77, the eight-cylinder motor 
used in the Briscoe 38, made by the Briscoe Motor Company, Jackson, 
Michigan, there are no unusual features. The single camshaft with 
16 cams is centrally placed in the middle of the V and operates the 
push rods, inclined outward, parallel to their respective groups of 
cylinders. A rocker arm, or follower, is used at the cylinder heads to 



Fig. 77. Section through Briscoe Eight, Showing Camshaft Arrangement 


transfer this up-and-down motion to the valves which are set in 
the center of the cylinder heads and are thus parallel to the push rods. 

In the majority of V-type motors, both eights and twelves, the 
valves are in side pockets, the cylinders being of the L-type, and thus 
there is no radical innovation except the inclined push rods and valve 
systems. In a few of these motors, however, a follower is used be¬ 
tween the cams and the push rods because of other structural reasons. 

When any kind of a cam follower is used differing from 
the usual direct-lift push rod, this may or may not affect 
the shape of the cam. Usually it does not, so that the shape 


269 


























110 


GASOLINE AUTOMOBILES 


does not have to be taken into account. Ordinarily these followers 
are used to prevent side thrust on the push-rod guide, the follower 
itself taking all the thrust and being so designed as to be readily 
removable or adjustable, to take care of this. In cases where this 

does not obtain, the object usually 
sought is the removal of noise. The 
two objects may be combined as in 
the case shown in Fig. 78. This 
represents an enlarged view of the 
cam mechanism of the famous one- 
cylinder French car, Peugeot. It 
will be clear that the action is that 
of one cam operating both the ex¬ 
haust and the inlet valves through 
the medium of a pair of levers, upon 
which the cam works alternately. 
Difficulties in Making Cams. 
There was a time when the production of a good, accurate camshaft 
was a big job in any machine shop, well-equipped or otherwise, and 
represented the expenditure of much money in jigs, tools, and fixtures. 
Now, however, the machine-tool builder has come to the rescue of the 



Fig. 79. Cams Integral with Shaft—Milling Machine Job 


automobile manufacturer, and special tools have made the work easy. 
So it was with the production of the shaft with integral cams; this 
used to be a big undertaking but, today, special machinery has made 
it an easy matter. The illustrations, Figs. 79 and 80, show some 



Fig. 80. Another Camshaft with Integral Cams 


of the product of a cam milling machine. This is now the favored 
way of putting out engines, for the integral cams and shaft have the 
advantage of much lower first cost and, with proper hardening, will 
last fully as long as those made by cutting the cams separately 
and assembling them in their proper position on the shaft. 
















GASOLINE AUTOMOBILES 


111 


Grinding Increases Accuracy. An even later improvement in 
the way of a machine for producing cams on an integral shaft is 
the grinding machine which has been developed for this purpose. 
This works to what is called a master camshaft—that is, a larger- 
sized shaft which has been very accurately finished. This master 
shaft is placed in the grinding machine, the construction of which 
is such that the grinding wheel follows the contour of the very 
accurate master shaft and produces a duplicate of it, only reduced 
in size, a reducing motion being used between master shaft and 
grinder-wheel shaft. 

The result of this arrangement is a machine which is almost 
human in its action, for it moves outward for the high points on the 
cams and inward for the low spots on the shaft. Moreover, it has 
this further advantage that all shafts turned out are absolutely alike 
and thus accurately interchangeable. It allows also of another 
arrangement of the work, the drop-forging of the shafts within a 
few thousandths of an inch of size; the surface of skin is easily ground 
off in one operation, then the hardening is done, and the final grinding 
to size is quickly accomplished, 
produced more cheaply than was 
formerly the case, and have in 
addition the merits brought out 
above, namely, greater accuracy, 
superior interchangeability, and 
quicker production. 

The same process is appli¬ 
cable to, and is used for, other 
parts of the modern motorcar; 
thus crankshafts are ground, 
pump and magneto shafts are 
finished by grinding, and many 
other applications of this process 
are utilized. The process can be extended indefinitely, the only 
drawback being that a master shaft is very expensive. 

Old Way Required More Accurate Inspection. With the old 
method of making the cams and shaft separate, the amount of 
inspection work was very great and represented a large total expense 
in the cost of the car. Thus, it was necessary to prove up every cam 


In this way, the shafts may be 



Fig. 81. English Cam Gage 


271 














112 


GASOLINE AUTOMOBILES 


separately, as well as every shaft, and, later, the cams and shaft 
assembled. One of the forms of gages used for inspecting cams 
is shown in Fig. 81. It is in two pieces, dovetailed together. This 
allows of the testing of many shapes of cam with but one base piece 
and a number of upper or profile pieces equal to the number of differ¬ 
ent cams to be tested. To test, the cam is slipped into the opening, 
and if small, the set screw forces it up into the formed part of the 
gage, showing its deficiencies; while if large, it will not enter the 
form. 

REPAIRING VALVES AND VALVE PARTS 
The interest of the repair man in all these valve-motion parts is 
quite different from that of the designer, for he cares not so much 

how they are made as 
how they are taken out, 
repaired, and put back, 
when accident or wear 
make this work neces¬ 
sary. To the repair man 
suitable tools for doing 
this kind of work are 
also of interest, par¬ 
ticularly those for reach¬ 
ing inaccessible parts 
or for doing things 
which without the tools could not be done. 

Curing a Noisy Tappet. Valve springs and the valves them¬ 
selves, either at the seat end or at the tappet end, give the most 
trouble. For example, when the clearance between the end of the 
tappet and the end of the valve (usually from tA<t to yAxr inch) is 
too great, a metallic click results. Often this noise from the tappet 
is mistaken for a motor knock; but the skilled repair man has little 
trouble in finding and remedying it, for even if he cannot measure 
in thousandths of an inch, he knows, for instance, that the ordinary 
cigarette paper is about tAo inch in thickness and from this he can 
estimate tAo, toW, or toio inch. Ordinary thin wrapping paper 
is well known to be about tAo inch; with this alone, or in combina¬ 
tion with cigarette papers he can obtain tA^, tAi>, tMtf, and tAo 
inch, practically all the variation he is likely to need. 


















GASOLINE AUTOMOBILES 


113 


Removing Valve. Getting the valve out frequently gives much 
trouble, the valve often being found frozen to its seat or with 
the stem gummed in its guide. A tool to meet this difficulty is a 
plain bar or round iron about J inch in diameter, Fig. 82, with one 
end, for a distance of perhaps 2 or inches, bent up at an angle 
of about 120 degrees. To use the tool, insert the short bent end in 
the exhaust or the inlet opening, according to which valve is stuck, 
until the end touches the under side of the valve head, then lower 
the outer end until the bottom of the bent part or point at which the 
bend occurs rests against solid metal. The outer end can now be 
pressed down, and with the inner end acting as a lever the valve can 
be pressed off its seat and out very quickly. 

To make this clearer, the rod, Fig. 82, is indicated at A, while 
the dotted line shows how 
it is pressed down and the 
valve forced out. The 
garage man can elaborate 
upon the tool when making 
it for himself by using square 
stock and having the inner 
end forked so as to bear on 
each side of the valve. The 
form pointed out above is 
the simplest, cheapest, and 
easiest to make. 

Removing Valve Spring. Taking out the valve spring is fre¬ 
quently difficult for various reasons; perhaps the springs are very 
stiff, or they may have rusted to the valve cups at the bottom, or 
the design may not allow room enough to work, etc. At any rate 
the removal is difficult, and a tool which will help in this and which 
is simple and cheap, is in demand. Many motor cylinders are cast 
with a slight projection or shelf opposite the valve spring positions, 
so that one only needs a tool that will encircle the lower end of the 



valve spring and rest upon this ledge, and give an outer leverage. 

In working on cylinders that do not have this cast projection, 
a tool like that shown in Fig. 83 is useful. It consists of a yoke for 
encircling the lower end of valve spring and cup, with a long outer 
arm for prying, and a slot into which is set a drilled bar. This bar 






114 


GASOLINE AUTOMOBILES 



Fig. 84. Type of Valve-Spring Tool Which 
Leaves the Hands Free 


is placed in various positions according to the kind of motor which 
is being worked on; when removing a valve-spring key, the lower 

end of the bar rests upon the 
crankcase upper surface, or 
upon the push-rod upper sur¬ 
face if that is extended. After 
slipping the grooved yoke 
under the spring cup, a sim¬ 
ple pressure on the outer end 
raises the valve so the key can 
be withdrawn. Then the removal of the tool allows the valve spring 
to drop down, and the valve is free. 

The valve spring may be removed in two other ways by the 

use of the two tools shown in 
Figs. 84 and 85. In the former, 
the idea is to compress the spring 
only, no other part being touched. 
This tool once set, will continue 
to hold the spring compressed, 
leaving the hands free—a decided 
advantage over the tool shown 
in Fig. 83. This device consists, 
as the illustration shows, of a 
pair of arms with forked inner 
ends and outer ends joined by a 
pin. A bent handled screw draws 
the ends together or separates 
them according to which way it 
is turned. 

The simplest tool of all is 
the one shown in Fig. 85, simply 
a formed piece of stiff sheet 
metal which is set into place 
when the valve is open. Then 
when the valve is closed by turning the motor, the sheet metal piece 
holds the spring up in its compressed position. 

Holding Valve Springs Compressed. Many times there is a 
need for holding the spring in its compressed form, as, for instance, 



Fig. 85. A Substitute for a Valve Spring 
Remover Which Pushes Spring Away 
as Motor is Turned 



































GASOLINE AUTOMOBILES 


115 


when the valve is removed with the positive certainty that it will be 
replaced within four or five minutes. In such a case a clamp which 
will hold it in compression is very useful for it saves both time and 
work. These may be made to the form shown in Fig. 86 in a few 
minutes’ time, for they consist simply of a pair of sheet metal strips 
with the ends bent over to form a very wide U shape. A pair of 
these is made for each separate make of valve spring, because of the 
varying lengths, but as they are so easily and quickly made this is 
no disadvantage. 

In many shops, after getting in the habit of making these 
clamps, the workmen take this way of replacing the spring in prefer¬ 
ence to all others. After removal of the valve, the spring may be 
compressed in a vise and a pair 
of the clamps put on. Then when 
the valve is ready to go back in, 
the spring is as easy to handle 
as any other part. This is es¬ 
pecially true when replacing the 
spring retainer and its lock. 

Stretching and Tempering 
Valve Springs. Many times 
when valve springs become weak¬ 
ened, they can be stretched to 
their former length, so that their 
original strength is restored. This 
can be done by removing them and stretching each individual coil, 
taking care to do it as evenly as possible. When well stretched, 
it is advisable to leave the coils that way for several days. This 
method will not, of course, restore the strength permanently; it is 
at best a makeshift, for in the course of a few thousand miles the 
springs will be as bad as before. 

Sometimes weakened valve springs may be renewed by retem¬ 
pering, on the theory that the original temper was not good or they 
would not have broken down in use. The tempering is done by 
heating to a blood-red color and quenching in whale oil. If this 
is not successful, new springs are advised. 

Adjusting Tension of Valves. Unless all the valves on a motor 
agree, it will run irregularly—that is, all the exhausts must be of 



275 













116 


GASOLINE AUTOMOBILES 


the same tension, and all the inlets must agree among themselves, 
though not necessarily with the exhausts. Many times irregular 
running of this kind, called “galloping”, is more difficult to trace 
and remove than missing or other more serious troubles, and it is 
fully as annoying to the owner as missing would be. 

To be certain of finding this trouble, the repair man should 
have a means of testing the strength of springs, a simple device 
being shown in Fig. 87. As will be seen, this consists of sheet-metal 
strips and connecting rods of light stock, with a hook at the top 
for a spring balance and a connection at the bottom to a pivoted 

hand lever for compressing the 
spring. By means of the center 
rod at R and the thumb screw 
at the bottom, the exact pressure 
required to compress the spring to 
a certain size may be determined. 
Thus, suppose the spring should 
compress from 4 inches to 3J 
inches under 50 pounds. By com- 



Fig. 87. Simple Rigging for Testing Valve 
Spring Pressure and Strength 


pressing it in the center portion 
of the device, so that the distance 
between the two adjacent strips 
of metal indicated by S is just 
3J inches, the spring balance 
should show just 50 pounds. If 
it shows any less, the spring is too 
weak and should be discarded; 
if it shows any more, it is stronger 
than normal—which is desirable if all the other springs on the same 
engine are stronger also. 

If only a quick comparison of four springs is desired, the device 
can be made without the bottom lever, as the setting of S at a 
definite figure—say to a template of exact length—would call for 
a certain reading of the scale of the spring balance. 

Cutting Valve Key Slots. Cutting valve key slots in valve 
stems is another mean job, which the repair man frequently meets. 
He runs across this in repairing old cars for which he has to make 
new valves and at other times. The best plan is to make a simple 





















GASOLINE AUTOMOBILES 


117 


Set Screw 
Valve Stem' 


Drill 



jig which will hold, guide, and measure, doing all these things at 
once as all are important. Such a jig is shown in Fig. 88. It con¬ 
sists of a piece of round or other 
bar stock, in which a central 
longitudinal hole is drilled to fit 
the valve stem, one end being 
threaded for a set screw. Near 

the other end of the jig, three Fig. 88. A Jig for Slotting Valve Stems Which 
. Can Be Made for a Few Cents 

holes are drilled in from the side, 

of such a diameter as to correspond with the width of key slot 
desired. These are so placed that the length from the top of the 
upper hole to the bottom of the lower gives the length of key seat 
desired. Opposite the three drilled holes and at right angles to 
them another hole is drilled 
and tapped for a set screw. 

To use the device, slip 
the valve in place and set the 
bottom screw of the jig so 
as to bring the three drilled 
holes at the correct height 
for the location of the key 
seat. Then the three holes 
are drilled, and the valve is 
moved upward so that the 
space between the holes is 
opposite a guide hole, and 
two more holes are drilled to 
take out the metal between. 

The five holes will give a 
fairly clean slot, which only 
needs a little cleaning up 
with a file, before using. 

SLIDING SLEEVE VALVES 

A method of avoiding 
cams, and with it all cam 
troubles, is the use of a sliding sleeve in place of a valve, slots in 
the sleeve corresponding to the usual valve openings, both as to area 



Fig. 89. Section through Ledru (French) Cam¬ 
less Engine. The Rotary Gear-Driven 
Sleeve Displaces All Cams 
































118 


GASOLINE AUTOMOBILES 


and timing. The sleeves may be operated by means of eccentrics, 
by various lever motions, or by a direct drive by means of a gear. 

Gear Control. An example of the application of a worm and 
gear for this purpose to a French two-cycle engine is shown in 
Fig. 89, although there is nothing in its construction which would 
prevent its use on the more usual four-cycle engine. 

In this figure, P is the usual crankshaft, Q the large end of the 
connecting rod K, while A is the piston and R the crank case, no 

one of these differing from 
those in other engines. On 
the crankshaft there is a 
large gear F, which drives a 
smaller gear E, located on a 
longitudinal shaft above and 
outside of the crank case. 
On this shaft is located a 
worm gear D, which meshes 
with a worm C formed in¬ 
tegral with the sleeve sur¬ 
rounding the piston B. 
Aside from this worm gear, 
the sleeve is perfectly cyl¬ 
indrical, being open at both 
ends. It is placed outside of 
the piston, between that and 
the cylinder walls. At its 
upper end, it has a number 
of ports or slots cut through 
it, which are correctly located 
vertically to register or coin¬ 
cide with the port openings 
in the cylinder walls, when 
the sleeve is rotated. At H 
is seen one of these—the exhaust, while 90 degrees around from it, 
and hence invisible in this figure, is a similar port for the inlet. As 
the crankshaft rotates, the side shaft carrying the worm is con¬ 
strained to turn also. This turns the worm which rotates the worm 
wheel and, with it, the sleeve. Thus the openings in the sleeve are 












































GASOLINE AUTOMOBILES 


119 


brought around to the proper openings in the cylinder and the 
combustion chamber is supplied with fresh gas, the burned gases 
being carried away at the correct time in the cycle of operations. 

With a motor of this sort, the greatest question is that of lubri¬ 
cation. The manner in which it is effected in this case is by means 
of the large wide spiral grooves shown at 00, and the smaller circular 
grooves at the upper end M. This problem is also rendered more 
easy of solution by the machining of the sleeve, as during this opera¬ 
tion much metal is cut away along the sides so that the sleeve does 
not bear against the cylinder walls along its whole length but only 
for a short length at the top and a still shorter length at the bottom. 

Eccentric and Lever Control. The same result is accomplished 
by the use of a combination of eccentrics and levers, as is indicated 
in Fig. 90, showing the idea of a New York inventor, Osborn. This 
scheme places upon the usual cam gear an eccentric pin, upon which 
is located an eccentric rod or lever A. The latter is pivoted at its 
lower end to a pin B, which pin is a part of a sliding member C, 
carrying upon its upper part a piston rod E. This slide reciprocates, 
according to the impulse imparted to it by the eccentric A, being 
guided by the slides D, which are fixed to the side of the crank case. 

Upon the upper end of the piston rod E is fixed a piston F , 
and slidably mounted around the whole is another piston valve J . 
The piston F is always moved by the rod, while the valve J is only 
moved upward by the collar at 7, its downward motion being pro¬ 
duced by a spring, not shown. G is the combustion chamber into 
which it is desired to lead the fuel mixture, and out of which the 
exhaust gases must afterward be taken, through the exhaust pipe II. 
IC is the inlet pipe, LL are the inlet ports, and M is the exhaust port. 
Unfortunately, this drawing shows the piston at the top of its move¬ 
ment, which would be more clear were it at the bottom. On the 
down stroke of the inner piston, moved positively by the eccentric, 
the exhaust gases rush down and out. On the same stroke, the 
inflowing gas fills the passage around the outside of the piston, so 
that when the exhaust stroke is completed, and the piston has risen 
so as to uncover the lower edge of the port through the walls 0, the 
gases are free to rush in, impelled by the suction of the motor piston. 
In the meantime, the rising outside sleeve has covered the exhaust 
port M, so that none of the mixture may escape to the outside air. 


279 


120 


GASOLINE AUTOMOBILES 


Knight Sleeve Valves. In the last few years, tremendous 
progress has been made here and abroad with the Knight motor, 
named after its Chicago inventor. In many important factories 
this has displaced those with the poppet form of valve. In this, a 
regular four-cylinder four-cycle engine, the valves consist of a pair 



of concentric sleeves, openings in the two performing the requisite 
functions of valves in the proper order. These sleeves, as Fig. 91 
shows, are actuated from a regular camshaft—running at half the 
crankshaft speed and driven by a silent chain—by means of a series 
of eccentrics and connecting rods. In the figure, A is the inner and 


280 





































































GASOLINE AUTOMOBILES 


121 


TABLE III 


Royal Automobile Club’s Committee Report on Knight Engine 


Motor horsepower—R. A. C. 

38.4 


22.85 

Bore and stroke. 

124 by 130 


96 by 130 

Minimum horsepower allowed .... 

50.8 


35.3 

Speed on bench test. 

1200 r.p.m. 


1400 r.p.m. 

Car weight on track. 

3805 lb. 


3332.5 1b. 

Car weight on road. 

4085 lb. 


3612.5 lb. 

Duration of bench test. 

134 hours 15 min. 

132 hours 58 min. 

Penalized stops. 

None 


None 

Non-penalized stops. 

Five—116 min. 


Two—17 min. 

Light load periods. 

19 min. 


41 min. 

Average horsepower. 

.54.3 


38.83 

Final bench test.. 

,5 hours 15 min. 


5 hours 2 min. 

Penalized stops.. 

None 


None 

Light load periods. 

15 min. 


1 min. 

Average horsepower. 

.57.25 


38.96 

Mileage on track. 

1930.5 


1914.1 

Mileage on road. 

.229 


229 

Total time on track. 

. 45 hours 32 min. 

45 hours 42 min. 

Average track speed.. 

1 

42.4 m. p. h. 


41.8 m.p. h. 

fFirst bench 

.679 pt. 

. .739 pt. 

Fuel per brake horsepower per hour! 

1 test. 

j Final bench 

.613 lb. 
.599 pt. 

.668 1b. 

.749 pt. 


l test. , 

.541 lb. 

.677 lb. 

Car miles per gallon.I 

[On track. . .. 

20.57 

22.44 

[On road. 

19.48 

19.48 

Ton miles per gallon.I 

I On track .... 

34.94 

33.37 

[On road. 

35.97 

31.19 


longer sleeve carrying at its lower end the groove or projection C, 
around and into which the collar actuating the sleeve is fixed. This 
collar is attached to the eccentric rod E, which is driven by the 
eccentric shaft shown. The collar D performs a similar function 
for the outer sleeve B. 

At the upper ends of both sleeves, slots G are cut through. 
These slots are so sized and located as to be brought into correct 
relations to one another and to the cylinder ports, exhaust at H and 
inlet at 7, in the course of the stroke. 

It might be thought that the sliding sleeves would eat up more 
power in internal friction than would be gained, but a very severe 
and especially thorough test of an engine of this type, made by the 
Royal Automobile Club of England, an unbiased body, proved that 
for its size, the power output was greater than that of many engines 
of the regulation type. Moreover, the amount of lubricating oil 
was small. 

The results of the test are shown in Table III. After the test 


281 





























122 


GASOLINE AUTOMOBILES 


was concluded, both of the sleeves, Fig. 92, were found to show still 
the original marks of the lathe tool. This proved conclusively that 
the principle of this type was right, for the tests were equivalent to 
an ordinary season’s running. 

Referring to Fig. 92, the slots which serve as valve ports are 
at G. The longer sleeve A is the inner one. At the bases of the 
sleeves are the collars and pins D by which the connecting rods are 
attached. The surfaces of the valves are grooved at J to produce 
proper distribution of oil. 



Fig. 92. Sleeves Which Replaced Valves on Knight Engine, after 
137-Hour Bench Test and 2200 Miles on the Road 


The Knight type of motor has been adopted by a number of 
well-known firms in America such as the Stearns, Willys, F. R. P., 
Brewster, and Moline Companies. These engines are noted for 
their silent running and for their efficiency. The Moline-Knight 
motor was in January, 1914, subjected to a severe continuous-run test 
of 337 hours under the auspices of the A. C. A. authorities. During 
this time the motor developed an average of 38.3 brake horsepower. 
For the 337th hour the throttle was opened and the motor developed 
a higher speed and a brake horsepower of 53. The test gives abun- 


282 



GASOLINE AUTOMOBILES 


123 


dant evidence of the endurance and reliability of the sleeve-valve 
type of motor and of the sterling qualities of the product of the 
American automobile manufacturers. After the test the motor 
parts showed no particular evidence of wear. 

In addition to the four-cylinder forms just mentioned, the 
Knight type of motor is also made as a six, and more recently, as 
a V-type eight. In these forms, the basic principle of sliding sleeves 
and their method of operation and timing is not changed. 

Originally, the Knight motor was installed only in the highest 
class cars. The firms in Europe which took it up ranked among 
the very first—notably the Daimler, Panhard, Minerva, etc.—but 
in this country it has made little progress among the better cars, 
and now it is assuming the rank of a low and medium priced motor, 
being available for about $1,000, and as an eight for approxi¬ 
mately $2,000. 


ROTATING VALVES 

Successful Operation Requires Two Valves. In addition to 
rotating and reciprocating sleeves and reciprocating valves, the 
rotating valve has been tried, in common with any number of other 
devices intended to supplant the ordinary poppet valve. This 
arrangement on a multicylinder motor consisted of a single valve 
for all the cylinders, which extends along the top or side of the 
cylinder head and is driven by shaft, chain, or otherwise, at one end. 
Naturally, this necessitated having the ports cut very accurately in 
the exterior of the valve, or rather the sleeve—for it usually assumed 
the form of a hollow shell—for not alone did it act as inlet and exhaust 
manifold but also as the timing device. This multiplicity of func¬ 
tions seems to have been its undoing, for the latest types using 
valves of this form have no longer one shell as at first, but a pair, 
one for the exhaust valves and one for the inlet valves. In the 
latter shape these have been more successful, but not sufficiently so 
to bring them into competition with the poppet and Knight sleeve 
valve forms. 

Roberts Rotary Valve. A motor—a two-cycle motor by the 
wa y_ w hich has been very successful in motorboat and aeroplane 
work although not much used for motorcars, is the Roberts, shown 
in Fig. 93, with the valve in Fig. 94. This valve is for the inlet 


283 




Fig. 94. Rotating Inlet Valve of Roberts Two-Cycle Motor 

should be replaced with great care, and after replacement it is fully 
as important to bolt it on properly. If one bolt or a series of bolts 
is tightened too quickly and too hard, it is likely to result in crack¬ 
ing the cylinder casting or the head casting or both. 

Proper Method of Bolting on Head. Usually on an L-head type 
of motor, there are three rows of bolts for the cylinder head—one 


124 GASOLINE AUTOMOBILES 

ports only, and is located inside the crank case, while the cylinders 
exhaust freely into the open air, the exhaust issueing directly from 
the cylinders. 

MISCELLANEOUS MOTOR REPAIR WORK 

Cylinder Heads. A great many motors have detachable heads 
and their quick removal is a great convenience, when there is carbon 


to be scraped off, pistons to be looked over, or other internal work 
to be done. However, replacing them is never quite so easy as 
removing them, partly on account of the cylinder heads themselves 
and partly on account of the pistons. The latter are particularly 
troublesome when the cylinder head is hinged. The cylinder head 


Fig. 93. Roberts Two-Cycle Motor with Rotating Crank-Case Valve 
Courtesy of E. W. Roberts, Sandusky, Ohio 













GASOLINE AUTOMOBILES 


125 


row along the middle, screwing into one side of the cylinders; 
another row screwing into the other side of the cylinders; and a third 
along the valve side. These should be tightened in order: first 
the middle bolts of the middle line, working out to the ends; 
next, in turn, the middle bolts of the back of the cylinder, the 
middle bolts of the valve side, the ends of the cylinder, and, 
finally, the end bolts on the valve side. All these should be 
tightened but a few turns at a time, and after all are down, a 
second round should be made in about the same order, to give 
each bolt a few more turns. In this way the cylinder head casting, 
which is both large and intricate, is slowly pulled down to the 
cylinder straight and true so that it is not warped or twisted. 
Moreover, if the cylinder is pulled down straight in this manner, 
all the bolts can be tightened 
more than if the first bolt were 
tightened very much, for that 
would result in cocking up the 
opposite side so that the bolts 
there could not be properly 
tightened. 

Rigging for Replacing Piston. 

In motors of the detachable head 
type, like the Willys shown in 
Fig. 91, the Chalmers, Briscoe, 
and others, the work of replacing the pistons, particularly if the 
crank case is cast integral with the cylinder block, is considerable. 
In fact it is sufficiently difficult to warrant making a special jig for 
guiding the pistons down into the long cylinder bores; this fastens 
onto the top of the cylinder where the head belongs. 

As shown in the sketch, Fig. 95, the jig consists of a round shell, 
the interior of which is at the bottom of the same bore as the cyl¬ 
inder, but flares out considerably at the top. The base consists of 
the flange needed for turning this in the lathe, and may be of any 
shape, size, and thickness. The action of the enlarged diameter at 
the top, gradually reducing to the exact cylinder size at the bottom, 
is to hold the piston rings in place and slowly contract them as the 
piston is lowered, so they pass down into the cylinder bore without 
trouble. One casting must be made for each cylinder bore, but the 



Fig. 95. A Simple and Easily Made Jig for 
Replacing Pistons in Detachable 
Head Motors 










126 


GASOLINE AUTOMOBILES 


time and trouble which they save and the injuries to workmen and 
parts which they avoid make them well worth while. 

Speeding up Old Engines by Lightening Pistons, Etc. As has 
been pointed out previously under Cams, one way to speed up an 
old engine is to replace the old camshaft and cams with new ones 
giving more modern timing. Another and a less expensive and 
troublesome way in which this can be done is by lightening the 
pistons and reciprocating parts. This the repair man will surely 
be called upon to do, as the manufacturer probably would refuse. 

In order to get out any 
amount of metal worth the 
trouble, it will be necessary 
to drill from 12 to 20 or more 
holes of from J-inch up to 
1-inch diameter, depending 
upon the size of the piston 
as to bore and length. In a 
six-cylinder motor, this 
amounts to almost 100 holes 
(even more in some cases), 
and as these must be drilled 
with considerable similarity 
in the pistons, it is well 
worth while to construct a 
fixture to aid or speed up 
this work. 

Clamp for Pistons. The 
first requisite is a clamp, Fig. 
96, to keep the piston from turning, so that it will not break the drill. 
A good way to begin is to construct a base with a pair of uprights 
having deep 90-degree V’s in them, this being made so that it can 
be bolted to the drill-press table. The V’s should be lined with 
leather or fabric, and for this purpose discarded clutch or brake linings 
answer very well. To one of the uprights is pivoted a long handle, 
having a lined V which matches with that of the upright below it 
and gives a good grip on the piston. 

Drilling Holes. When drilling to save weight, the holes are 
put in close together, and in regular form, the idea being to take out 



Fig. 96. A Home-Made Wooden Stand to 
Facilitate Drilling Out Pistons 


286 











GASOLINE AUTOMOBILES 


127 


as much weight of metal as is safe. In doing this it is well to work 
out a scheme of drilling in advance and to make a heavy brown 
paper template, fastening this to each piston in turn. It is not 
advisable to remove in the first instance all the metal possible, but 
only enough to show the benefit of the method; after it has proved 
satisfactory, the first job may be improved upon later. For instance, 
in lightening pistons it is a good plan to use a f-inch drill the first 
time and not to put in too many holes. If this proves satisfactory 
and the owner comes back for more, you can go over the same lot 
of pistons, using a J-inch or f-inch drill between the existing holes, and 
thus reducing the weight of the lower end of the piston to its lowest 
possible point. 

Curing Excessive Lubrication. Holes in Cylinders. When it 
comes to drilling holes, to provide an outlet for the excess oil in the 
cylinders and so to reduce smoking, small 
holes, J-inch for example, are sufficient 
and may be drilled in on any spiral plan, 
simply beginning near the bottom and 
working up close to the piston pin bosses 
along a spiral track. The advantage of 
the spiral arrangement is that no hole 
is above another; the dripping from each 
hole is therefore distinct and the quantity 
which runs down is greater. 

Grooving Pistons. Another method of 
curing the excessive lubrication to which 
the older cars—particularly those with 
splash lubrication—are subject, is to turn a deep groove in the bottom 
of the piston, about like a piston ring groove but with the lower edge 
beveled off. When this is done, much as shown in Fig. 97, a series 
of small holes—made with about a No. 30 drill—are put in at the 
angle of the bevel; 6 or 8 holes, equally distributed around the cir¬ 
cumference, are probably enough. The sharp upper edge acts as a 
wiper and removes the oil from the cylinder walls into the groove, 
whence it passes through the holes to the piston interior, and there 
drops back into the crankcase. No ring is placed in the slot as it 
would prevent the free passage of the oil. This device stops the 
smoking immediately. 



Fig. 97. Method of Grooving and 
Drilling Piston to Overcome 
Excessive Lubrication 
and Smoking 


287 


















128 


GASOLINE AUTOMOBILES 


Piston Troubles. Frozen or Clogged Pistons. Sometimes, the 
pistons will apparently be frozen in the cylinders, particularly in 
very cold weather and when fairly thick oil is used. This is but a 
temporary trouble and can be cured by pouring in a thin oil or, 
better yet, kerosene. The thin oil will work more quickly if heated, 
and should be poured in on top of the pistons, either through the 
petcock, valve-cap opening, or other available opening in the top of 
the cylinder. Being thin—and if hot, thinner than usual—the 
oil will work down between piston and cylinder walls, cutting 
through the thicker oil which has hardened there under the influence 
of the cold weather, and thus will free the pistons. 

Loose Pistons. Many times the pistons will wear just enough so 
that they are loose in the cylinder all the way around. This causes 
leakage of gas, piston slaps, and other similar troubles. If the owner of 
the car does not care to buy new pistons, or if the car is an “orphan”, 
or if, for other reasons, pistons cannot be obtained, the clever repair 
man can remedy the trouble at small expense. The process consists 
in heating and expanding the old pistons. The heating is done 
in charcoal and must be done very carefully and slowly. After 
the pistons become red hot the fire is allowed to go out slowly, so 
that the piston is cooled in its charcoal bed. Sometimes as much 
as toW of an inch can be gained in this way. When the pistons are 
so far gone that they cannot be handled in this way, they must be 
replaced with new ones. 

Use of Oversize Pistons with Worn Cylinders. When the cylin¬ 
ders have worn so as to require grinding out, or when scoring neces¬ 
sitates this, oversize pistons must be used. In the majority of 
factories having any kind of system, three oversizes are made t 
inch over, yA^-inch over, and yAo-inch over. The first provides 
for the initial grinding-out of the cylinder, the second for the second 
grinding, and the third for a lighter, final grinding. Beyond this, it 
is considered, the cylinder will be too thin to warrant further grind¬ 
ing; moreover, by the time three cylinder grindings have been lived 
out, the balance of the car will doubtless be too far gone to justify 
further cylinder repair work. Many factories, particularly those 
making a very light-weight car where thicknesses everywhere are 
kept down to the limit, allow but two oversizes, and thus, two 
grindings. 


288 


GASOLINE AUTOMOBILES 


129 



Fig. 98. Original De Dion Surface 
Carbureter 


CARBURETERS 

Classification. Classified as to structure, operation, and prin¬ 
ciple, all fuel vaporizing devices may be divided into three main 
groups, which are as follows: 

(1) The surface carbureter 

(2) The ebullition or filter¬ 
ing carbureter 

(3) The float-feed or 
spraying carbureter 

As most of the modern de¬ 
vices come in the last-named 
class, it will be sufficient to 
speak of the other two briefly. 

The early devices were mainly 
of the surface type, in which the 
air passed over the surface of a 
body of fuel, picking up some of 
it, Fig. 98. Another early form 
circulated the air around gauze, 
wicking, or other surface saturated with fuel, Fig. 99. Benz used 
a vaporizing device of this sort in his earlier machines. Both of 
these methods are in use today, but in combination, and not as 
the sole source of gas. 

Another very old 
device is called the ebulli¬ 
tion or filtering carbu¬ 
reter. In this, air was 
forced through a body of 
liquid, which entered at 
the bottom and in its 
passage to the top ab¬ 
sorbed small particles of 
the fuel. Daimler began 
with this style, but later 
abandoned it in favor of 
the Maybach float-feed spraying arrangement, which was the pro¬ 
totype of the form now in prevailing use. The filtering scheme is, 
however, still used. 



Fig. 99. Wick Vaporizing Device 


289 


















































130 


GASOLINE AUTOMOBILES 



Fig. 100. Original Maybach Carbureter 


A fourth, and the most common, basis of operation, is the 
spraying or atomizing of the liquid - through a very fine nozzle, the 
vapor being picked up by the inrushing air. The first of this type, 
the Maybach, Fig. 100, was remarkable, in comparison with its 
modern successor, principally for its simplicity. There was a float, 

controlled by the amount 
of liquid, and a nozzle. 
The air entered around 
the nozzle and, mixing 
with the fine spray of fuel 
in a chamber directly 
above the cylinder, was 
drawn from there into 
the combustion chamber. 
Although simple, it was 
also crude and the heat 
from the cylinder doubt¬ 
less had much to do with its success. The nozzle was large, as such 
sizes go today, but in spite of all these defects it worked, and worked 
better than anything that preceded it. 

Defects in the Original Are Not Found in Modern Types. The 
original carbureter had no adjustment; the opening in the casting 
measured the amount of air; the size of the nozzle measured the 
amount of the fuel and the fineness of the spray. There was no 
means of regrinding the float valve, and thus no way of assuring 
an even and continuous flow of fuel. The modern adjuncts of the 
original Maybach device consist of remedies for these defects, and, 
in addition, a proper means of balancing and adjusting the float. 

To pick out a modern carbureter at random, take the one shown 
in Fig. 101. Like its ancestor, this has a gasoline chamber into 
which the fuel is admitted by the action of a float, first passing 
through a strainer. From the float chamber the liquid passes up to 
and through the spraying nozzle. The weight of the float is so calcu¬ 
lated that the level in the final nozzle is just 1 millimeter (0.04 inch) 
below the top. This insures that there will always be fuel there for 
the air suction to draw off. As the physical action of changing a 
substance from a liquid to a gas is usually accompanied by the 
absorption of heat, it is advisable to supply a reasonable proportion 


290 





































Gasoline Needle Valve 


GASOLINE AUTOMOBILES 


131 



291 


Fig. 101. Type H Carbureter with Venturi-Shaped Mixing Chamber 
Courtesy of Stromberg Motor Devices Company, Chicago 

























































































132 


GASOLINE AUTOMOBILES 


of this and thus assist the change of form. In the older Maybach, 
this was inadvertently done by placing the whole apparatus in close 
contact with the hot cylinder. In the modern carbureter, placed 
some distance from the heated portions of the engine, this additional 

heat is supplied by the jacket 
water. An alternate scheme is 
to pre-heat the air supply by a 
special pipe from the exhaust 
manifold. 

From this mixing chamber 
the mixture of air and gasoline 
vapor passes upward into a sec¬ 
ondary mixing chamber. This 
communicates with the inlet pipe 
through the medium of the throt¬ 
tle valve. Into the latter cham¬ 
ber, the auxiliary air supply— 
when used—has access through 
the auxiliary air valve. This 
comes into action on very high 
speeds when the engine is pulling 
very strongly, for which the pro¬ 
portion of gasoline to air is apt 
to be too large, so the auxiliary 
opens, admits more air, and thus 
dilutes the mixture. 

Throttle Valves. Butterfly 
Type. Whatever the nature of 
the mixture in the carbureter, it 
is admitted to the cylinder by 
the throttle valve, which may take 
the form known as the butterfly. 
This is a flat piece of sheet metal, preferably brass, attached to a 
suitable shaft with an operating lever on the external end. 

Piston Type. Besides the butterfly there are fully as many of 
the piston type. The sliding form is a cylindrical ring or shell of 
metal, which is free to slide in a corresponding cylindrical chamber. 
In the walls of the latter are a number of apertures or ports which 



Fig. 102. Carbureter and Inlet Pipe of Gag- 
genau (German) Commercial Vehicle 


292 


















































GASOLINE AUTOMOBILES 


133 


the longitudinal movement of the piston either uncovers or covers as 
the case may be. Sometimes, to facilitate this action, the sides of 
the piston are grooved or notched, but this does not alter the prin¬ 
ciple of sliding a cylinder within another cylinder to cover or uncover 
certain ports in the cylinder walls. This form of throttle is used 
and advocated by such prominent firms as Napier, Panhard, Krebs, 
and other equally famous constructors. 

In addition to the sliding piston, there is the rotating piston, 
working in practically the same manner, that is, its rotation connects 
openings in the piston walls with the interior of the vaporizing 
chamber on one side and with the inlet manifold on the other, the 
amount of the opening depending upon the distance the piston is 
rotated. This form is used by many prominent makers, such as 
Gaggenau, Fig. 102, the 
G. and A., Daimler, 

Benz, and others. The 
Wildi, De Dion, Saurer, 
and Senrab are advo¬ 
cates of the sliding-piston 
type, while the Siddeley 
is a combination of both 
the sliding and the rotat- Fig. 103 . 
ing forms. 

Needle Valves. Needle valves—or spray nozzles as they are 
sometimes called because of the function they perform constitute 
an important part of every carbureter or liquid-vaporizing device. 
It might be thought that so long as there is a hole by which the fuel 
can'enter the vaporizing chamber that is sufficient; yet such is far 
from the case. In addition to the function of an entering hole, the 
needle has the additional duty of breaking the fuel up into a fine 
spray or mist, the particles of which are easily picked up by the 
inrushing air, and as easily converted into a vapor. This being the 
case, that shape, form, or arrangement which will divide the entering 
liquid up into the finest particles will be the most efficient. The 
difference of opinion on this latter point has produced the large 
number of shapes of nozzle and needle which are now in use. 

Simple Vertical Tube . In general, practically all of these can 
be divided into four groups, illustrated' in Fig. 103. 




The Four Usual Shapes of Gasoline Needle 
Valves and Spray Nozzles 


The one at A 


293 


















134 


GASOLINE AUTOMOBILES 


is a simple round vertical tube with an opening in the top, through 
which the liquid may pass out. It does not alter the type if the 
sides of the opening converge, diverge, or are straight, but it will 
influence the resulting spray somewhat. Of the twelve makes shown 
with this type, practically all indicate the opening as straight, but 
this may be due to the small size of the drawing which does not make 
the taper apparent. 

Internal Needle Type. Type B, Fig. 103, is similar to the first, 
except that an adjustable pointed needle is added on the inside. 
This occupies most of the center space, forcing the liquid to pass out 
in a smaller circular sheet or stream than would be the case with 
Type A, considering equal-sized holes. In addition, the fact that the 
internal needle valve may be raised or lowered allows of varying 
this stream greatly, both as to quantity of fuel flowing and extent 
to which it is spread out. When the needle is down very low, only 
its point enters the hole, so that practically the full area of the latter 
is available, the central needle influencing the column of fuel passing 
out only to make it hollow in the center. 

; With the needle raised to nearly its maximum height, however, 
the point projects clear through and the needle shaft almost fills the 
lower part of the hole. This reduces the flow to a very fine hollow 
column of spray and, in addition, the shape of the needle and lower 
edge of the hole is such as to force it inward and then outward so 
that as it leaves the top of the hole it is diverging widely. Thus, the 
effect of the addition of the needle is to allow the use of much smaller 
quantities of liquid with the same sized hole, of diffusing it more 
widely, and of making it adjustable to varying needs. Despite 
all its advantages, only three of the carbureters and vaporizers shown 
use this type and of these, one is a combination of this with A. 

External Needle Type. The third type shown at C , Fig. 103, is an 
inversion of B in that the needle is made external and descends from 
above into the hole in the nozzle. In this form, the shape of the 
needle point produces the desired diffusion and spraying effect, which 
accounts for its popularity. Of the models shown herewith, nine are 
of this kind, one being a modified combination of this form and A. 

External Sectional Needle Type. The fourth form, shown at D, 
is like C, except that instead of a needle resting upon the upper 
surface of the hole and allowing a continuous hollow stream of fuel 


294 


GASOLINE AUTOMOBILES 


135 


to flow, a series of holes break up the column into a number of very 
much smaller columns, each with its own opening. In this form the 
central member may be movable or not, while the holes may be set 
at any angle. In fact, of the examples of this form shown in this 
article, three in all, every one has the holes placed horizontally 
instead of inclined to a vertical, as shown in Fig. 103. Of these, two 
show a combination of B and D. This is an effective combination. 

Floats. Another feature of the earlier forms of carbureters, 
which was soon found to be in need of a change, was the arrange¬ 
ment of the float. In Maybach’s original vaporizer, there was no 
means of balancing the float; consequently, there was no way of 
preventing wrenching and breaking of the needle valve spindle. As 
this disarranged the gasoline supply, it was very important and 
received early attention. In addition, there was the necessity for 
reliable devices to regulate the supply of air and gasoline spray from 
the nozzle, either by original adjustment or by means of a governor, 
or else effecting by hand a constant variation to meet constantly 
varying conditions of engine demands. 

These additions to the original form caused some trouble. 
The ordinary way of managing the balancing of the float, while it 
may be the cause of trouble at times, is a very simple one. The float 
is of exceeding lightness, whether made of cork or metal. With 
the inflow of gasoline in liquid form this float rises and in so doing 
it strikes against a pair of small pivoted levers near the top of the 
float chamber, Fig. 102; the other ends of both of these rest upon a 
form of shifting collar on the needle valve stem. So, when the float 
rises above a certain level, it automatically shuts off the flow of 
gasoline, by pressing against the pivoted levers, which, in turn, act 
against the stem and press it down until the flow is cut off. The 
float will stay up until the suction of the engine has lowered the 
gasoline level so that the dropping of the float releases the levers 
which raise the needle valve off of its seat. The gasoline flow is thus 
automatically regulated by this balanced float arrangement. 

ADJUSTMENT OF AIR AND GASOLINE SUPPLY 

Methods of Handling Fuel Spray. Probably no one detail 
of the whole list of carbureter parts has caused, and still does cause, 
more difference of opinion than the source of and adjustment of the 


136 


GASOLINE AUTOMOBILES 


air supply, and its companion, the adjustment of the gasoline spray. 
The latter drew attention long before the former did; in fact, the 
former is more of a modern appliance. The fuel spray was inves¬ 
tigated long ago; thus the gasoline spray had no adjustment, but 
the size and location of the level of the nozzle were fixed. The 
spray itself, however, received special treatment, being projected 
against a conical spray deflector, which served to break up the 
column into finer and more diffused particles. In this way, greater 
vaporizing action was gained. 

Complicated Longuemare Type. Longuemare, the French car¬ 
bureter expert, divided the spray, before the air struck it, into a 
circular column of finely divided particles, Fig. 104. These were 
then easily picked up by the incoming air, which in its upward 
passage was further diluted by the addition of more air. The latter 
was added at a point where the carbureted gas was obliged to turn 
a right angle, at which any remaining particles of pure gas would 
have been thrown off by centrifugal force. The downcoming stream 
of extra air met these particles and by carrying them along prevented 
what would otherwise have been a waste of fuel. This carbureter 
has long been noted for its fuel economy. 

In Fig. 104, A is the float chamber, containing the hollow metal 
float B. Gasoline enters from below, I being the gasoline pipe con¬ 
nection, J the drain cock, and H the gasoline chamber with the 
needle valve at the top. At the top of the float chamber the small 
lever for priming may be seen at E, while C is the removable cover, 
with the bushing D covering the end of the needle-valve shaft. The 
gasoline flows across the horizontal passage to the vertical one, in 
which the spray nozzle is located. This spray is formed by the fuel 
passing through the small orifice formed between the restricted upper 
part of the vertical passage and the point of the needle L. Just above 
this, so that the spray impinges upon it, is placed an inverted cone, 
which deflects the gasoline spray down again and outward through 
short horizontal apertures M. Around these openings is placed a 
hollow cylindrical shell N, open at the top and with holes K in 
the bottom. 

The supply of air rushes in through these holes, and picking up 
the gasoline spray, passes along out of the top of the cylinder, being 
augmented outside by additional air rising around the outside of the 


GASOLINE AUTOMOBILES 


137 




nnnf 


Fig. 104. Longuemare (French) Carbureter Arranged for Alcoho Fig. 105, Section of the Ford Carbureter 

































































































138 


GASOLINE AUTOMOBILES 


cylindrical shell N. The mixture then passes upward through the 
diaphragm filled with holes 0 , and thence into the pipe to the cylin¬ 
ders Y. X is the air inlet. The auxiliary air enters at the top, its 
entrance being controlled by the balance established between the 
weight with two arms dd and the central spring. The two small 
openings ee indicate the location of the auxiliary air pipe, while 
V is the water jacket—at the time this particular model was brought 
out, however, it was used as a hot-air jacket, instead of the more 
modern hot water. The lever S controls the amount of mixture 
admitted, while the handwheel / governs the adjustment of the 
needle L. 

Simple Ford Design. The possible simplicity of the carbureter 
is nowhere better shown than in the Ford device, Fig. 105. This 
affords at the same time a free comparison with the complication 
and large number of parts of the Longuemare, just described. In 
the Ford, A is the thumbscrew with an extension to the clutch, by 
means of which the needle valve B is raised or lowered. The lower 
end of this projects down into the spray nozzle C, where the fuel 
enters from the float chamber D. It reaches the latter through the 
gasoline intake E , shown at the right. Sediment and water are 
drawn off by means of the cock F at the bottom. 

From the nozzle, the fuel passes up through the strangling tube 
G where it is met by the entering air from the air inlet H, which has 
been deflected downward and toward the center of this circular space 
so as to pick up the spray of fuel at the nozzle and carry it upwards 
in the strangling tube. Then it passes into the mixing tube N, 
thence out to the motor via the mixture outlet 7. In this, its quan¬ 
tity is governed by the throttle, the lever on which may be seen at 
J. In the air intake, there is a throttle plate K, which deflects a 
large part of the entering air so that it passes to the right, straight in, 
and is added to the mixture in the mixer chamber, this forming the 
auxiliary air valve. The position of this plate, governed by the 
auxiliary throttle lever L, determines the quantity of both the 
primary and auxiliary air since by its position it splits the entering 
air into two parts, one of which becomes the primary air, and the 
other the auxiliary air. For low speeds and idling, the low speed 
tube M carries the very rich mixture up direct to the mixing chamber 
and thus into the engine. 


298 


GASOLINE AUTOMOBILES 


139 


Water=Jacketing. Longuemare was among the first to use a 
water jacket around the vaporizing chamber. The conversion of a 
liquid into a gas is an endothermic reaction and requires heat for its 
completion. If this be not supplied by external means, it will be 
extracted from surrounding objects. This accounts for the frost 
which gathers on the outside of the mixing chamber of carbureters 
which do not have a water jacket or other source of heat supply. 
The heat is abstracted from the air so rapidly that the moisture in 
the air is frozen, appearing as frost on the outside of the carbureter. 

Auxiliary Air Valve. The auxiliary air valve has always caused 
discussion, its opponents claiming that it means extra parts, and 
therefore more adjustments and more sources of trouble; while those 
favoring it say that without some additional means of this sort for 
diluting the mixture at high speeds, it is impossible to run the engine 
fast, as high speed will then mean an over-rich charge. Be that 
as it may, the fact remains that the weight of opinion lies with the 
auxiliary valve. 

Necessity with Heavy Fuels. Practically all of the more modern 
vaporizers use an auxiliary air valve, this being a partial necessity 
with the heavier fuels. That is, it has been found that the heavier 
fuels require more air to vaporize them than can be supplied by the 
primary air inlet. Moreover, these heavy fuels require considerable 
additional heat in order to vaporize and the auxiliary air inlet has 
been made the vehicle for conveying this. As will be explained in 
detail later on, this is generally connected with the exhaust manifold 
in such a way that the air entering through it is heated to a high 
temperature. Adding this after the fuel has been split up by the 
spraying nozzle and the primary air has proven very successful. 

Usual Forms of Auxiliary Air Inlet Valve. The auxiliary air 
inlet usually consists of a simple valve, opening inward, held in its 
place by a spring of a certain known tension. The strength of the 
spring is carefully determined so that at the proper moment when 
the motor requires more air in proportion to the amount of gasoline 
used—the valve will open just enough to allow the required amount 
of air to enter. It will be seen that the time and the amount of 
opening will be controlled by the speed of the engine, i.e., by the 
amount of suction produced by the movement of the piston in the 
cylinder. Of course, as the engine speeds up, there is a greater 


299 


140 


GASOLINE AUTOMOBILES 


piston displacement to be filled per minute, and therefore it is neces¬ 
sary to supply a greater amount of mixture. Upon changing speed 
suddenly from, say, 500 revolutions to 900 or 1000, the carbureter 
not having this device will not give a uniform mixture immediately, 
and, in fact, it might require a new adjustment of the gasoline flow 
in order to supply the right amount of fuel. What the auxiliary air 
inlet actually does, then, is to control automatically, above a certain 
point, the amount of air admitted, thereby always maintaining a 

homogeneous mixture. In 
order to prevent any chat¬ 
tering of the valve or rapid 
changes in the air supply, a 
diaphragm or a dashpot is 
sometimes used in connec¬ 
tion with the valve. Fig. 
106 is an example of the 
dashpot form. In this figure, 
B is a short piston formed 
on the lower end of the 
throttle valve stem C. This 
piston works up and down 
with the motion of the throt¬ 
tle, its action being opposed 
by the immobility of the 
liquid placed in the dashpot 
A. This quality of liquids 
prevents sudden changes in 
the fuel supply to the engine, 
which changes are not desir- 

Fig. 106. Dashpot to Regulate Air Supply , . i i • » 

able—a sudden increase of 
mixture, for instance, causing racing, while an equally sudden 
decrease will stall the engine. To obviate any difficulties which 
might arise from the use of several different liquids, the gasoline 
itself is used as the liquid for the dashpot, the by-pass at the right 
leading it into the dashpot. In all other particulars the carbureter 
follows standard practice. 

Ball Type of Auxiliary Valve. A valve adopted by the makers 
of the G. and A. (short for Grouvelle and Arquembourg) carbureter 














































301 


Fig. 107. Elevation and Section of Original Venturi Tube Carbureter 

Grouvelle et Arquembourg , Paris 






















































































































































































































142 


GASOLINE AUTOMOBILES 


avoids the principal argument against the auxiliary valve. A row 
of steel balls A A, Fig. 107, are set into as many holes in the ball 
casing B, which communicate with the outer air on the lower side. 
The balls are free to rise vertically and are of varying sizes from one- 
eighth inch to about three-eighths inch in diameter. As the engine 
speeds up and draws on the mixture chamber, the lighter and smaller 
balls are lifted off their seats, admitting a small amount of air. 
With greater speed and consequently greater draft, larger and larger 
sized balls are lifted, admitting more and more air. There are no 
springs to bother with and no adjustments, the number and size of 
the balls, which have been carefully adjusted by the manufacturer, 
being equivalent to this. 

Carbureter in Inlet Pipe. The expense of making the carbureter 
may be lessened by incorporating it in the inlet pipe. This is fre¬ 
quently done in European cars, as shown in the Wildi type, Fig. 108. 
This form uses the piston throttle but, contrary to that of all others 
shown, the movement is in a vertical direction. 

This throttle valve A is located on the low T er end of the throttle 
stem B, to which is connected the operating levers. The piston 
throttle A has a row of large holes near the top, through which the 
mixture passes when the throttle is raised sufficiently to permit this. 
A still further upward movement uncovers additional air holes 
through the exterior casing C of the carbureter. The remaining 
actions of the device either are self-evident or follow standard lines. 
The heating of the gasoline, previous to vaporization by the aid of the 
exhaust gases around the fuel chamber, will be noticed. 

Venturi Tube Mixing Chamber. Like every other carbureter 
part, the spraying action and the shape or size of the chamber in 
which it takes place have been the subject of much debate. Orig¬ 
inally, the chamber took any convenient shape and varied all the 
way from a perfectly plain cylindrical shape to an equally perfect 
square, with all of the possible variations in between. A few years 
ago, however, scientists began to look into the vaporizing and equally 
important measuring action of carbureters, with the result that a 
new shape came into use, which was based upon a scientific principle. 

This is the principle of the Venturi meter used for measuring 
the flow of water, and from its use, the tube, or chamber, having 
this shape has come to be known as a Venturi tube. In form, this 


302 


GASOLINE AUTOMOBILES 


143 


consists of two cone-shaped tubes diverging in opposite directions 
from a common point, which in the water meter is the 'point of meas¬ 
urement and in the carbureter is the point of location of the spray 
nozzle. The principle is that if these two frustrums of cones are of 
the proper shape, i.e., include the proper angle, and are correctly set 
with relation to one another, the flow of air and gas will be in correct 
proportions to each other at all speeds, assuming first that the air 
enters at the bottom of the tube 
having the greater angle. 

As a proof of the soundness 
of the principle of this type of 
vaporizing chamber, it might be 
said that the majority of carbu¬ 
reters in use today have it incor¬ 
porated in one form or another, 
as seen in Fig. 112 and others 
following. Many make the upper 
tube conical for a very short dis¬ 
tance, beyond which it assumes 
a cylindrical form. In the true 
Venturi shape, the usual angle 
at the bottom is 30 degrees, while 
that at the top is 5 degrees. In 
water meters the contracted area 
is made one-ninth that of the 
pipe. This same relation, al¬ 
though not exact, holds in the 
case of the carbureter. Since 
the area varies as the square of 
the diameter, this is equivalent to saying that the diameter of the 
contraction should be one-third the full-sized pipe. 

Standard Practice. In order to study the development of the 
carbureter let us consider a few examples. In Figs. 109 and 110 are 
shown two views in section of the De Dion carbureter. These illus¬ 
trations show a number of interesting small points, close attention to 
which have made the French the foremost automobile constructors. 

Of these two views, Fig. 109 shows the carbureter, while Fig. 110 
shows the throttle chamber located higher up in the inlet pipe, and 










144 


GASOLINE AUTOMOBILES 


very close to the cylinders. In Fig. 109, the gasoline enters through 
the pipe A, passes through the gauze strainer I, through the needle 
valve into the float chamber, thence, through B into the pool C. 

From this a vertical pipe 
D rises to the spray noz¬ 
zle E. Air enters at the 
base through the holes 
G y passing upward around 
the standpipe D f vapor¬ 
izing the liquid at the 
top of the latter, and 
passing on through the 
pipe H to the engine. 
Before it can do this, 
however, it must pass 
through the throttle, Fig. 
110. In this, H is the 
mixture pipe as before, 
which reaches a throttle 

Fig. 109. De Dion Carbureter Showing Strainer valve J of the piston 

and Float Chamber r 

type, in the walls of the 
open end of which are holes K through which the mixture enters. 
When withdrawn sufficiently to the left, the end of the piston clears 
the edge of the mixture pipe, so that the mixture may then pass 

directly into it instead of 
passing through the holes. 
L is the connection to 
the cylinders through 
which all gas mixture 
ultimately passes. 

In this chamber more 
air is added. This enters 
by the ports M, and 

Fig. 110. Details of De Dion Throttle and Spring through the Valve 2V. The 
Tension Adjuster . 

action of the latter is con¬ 
trolled by the spring 0, which may be adjusted to any desired tension 
by means of the movable slide P. Since this has a tapered end, moving 
it in raises the stem, compresses the spring, and renders the auxiliary 




304 


































GASOLINE AUTOMOBILES 


145 



Fig. 111. Section through the Edwards Carbureter, 
Showing Bellows, Piston, and Needle Valve, and at 
Left, Float Chamber 


air valve more difficult to open. Consequently less air may enter. 
Drawing the wedge-shaped end outward has just the opposite effect. 

A decidedly different 
yet most interesting de¬ 
vice is the Edwards car¬ 
bureter, made by the 
National Carbureter 
Company, of Chicago, 
and shown in Fig. 111. 

The first thing to note is 
that the spray nozzle and 
needle valve A are set at 
an angle of 30° with the 
horizontal. In addition, 
this forms but the inner 
end of the mechanism by 
which the nozzle opening 
is made self-controlling. 

At the outer end is a bel¬ 
lows chamber with a col¬ 
lapsible bellows B con¬ 
nected by means of the 
passage F to the mixing 
chamber below the throt¬ 
tle. In this way, the 
pressure on the bellows is 
always that of the mixing 
chamber. The shaft, if 
it might be called that, 
which has for its lower 
end the needle valve, is 
guided by means of the 
weighted piston C. In 
this way it will be noted 
that this unit governs the 
fuel opening. Note also that the air enters at D on a curve, and that 
the piston C by its position also governs this air opening. When at rest, 
the weight of the piston keeps it down so that it is but & inch from 



Fig. 


112. Decauville (French) Carbureter Using 
Tapered Mixing Chamber 


305 

















































146 


GASOLINE AUTOMOBILES 


the jet, the latter being practically cut off. This gives a great rush 
of air at the start, but as soon as the throttle is opened the pressure in 
the mixing chamber falls, so that the bellows contracts, drawing up 
the needle and with it the piston, thus giving more fuel and air at 
the same time. With still greater suction, the pressure goes even 
lower, producing, automatically, more fuel and more air. This 
device will use kerosene readily, if the air entering at D is pre-heated. 



Fig. 113. Argyll (Scotch) Carbureter with Liberal Air Passages 


A popular French design is the Decauville, Fig. 112, the mixing 
chamber showing a strong taper shape. Quite a different design 
showing the characteristic Venturi shape, is the Argyll carbureter, 
Fig. 113. This type has exceptionally large air passages. 

One of the foremost English makers, Siddeley, has been a stead¬ 
fast advocate of the horizontal opposed engine. For this form he has 
developed an unusual and very efficient carburetion system. As 
shown in Figs. 114 and 115, this differs from the ordinary vaporizer 
in having a peculiarly shaped auxiliary air valve and in the method of 
operating this and the piston throttle valve. 

































GASOLINE AUTOMOBILES 


147 


To explain the operation clearly, Fig. 114 and Fig. 115 must 
be considered together, as the latter is but the end of the vaporiza- 



Fig. 114. Section Through Siddeley 
(English) Carbureter 



Fig. 115. Siddeley Mixing Chamber and 
Inlet Pipe 


tion system, while the former is the starting point of it. Gasoline 
from the tank enters at A, passes through the usual float chamber 



Fig. 116. Daimler Carbureter, Shown in Two Sections 
Daimler Actiengesellschaft, Untertiirkheim, Germany 


B into the standpipe C. Air enters at D, vaporizing the gasoline 
in the chamber E. The upper end of this, Fig. 115, tapers down to 


307 










































































































































148 


GASOLINE AUTOMOBILES 


a small point, while the additional air enters it from above through 
the flat-seated valve G. The two are mixed in the chamber F, and 
thence pass through the throttle valve. This consists of two parts 
the outer, H, being a rotary piston, operated for normal running by 
the lever J. Within this piston, however, is a sliding piston throttle 
L, which is operated by the additional lever K. The two in combi¬ 
nation allow many and varied combinations of rich and lean mixtures 
to enter the inlet pipe 7-7, and through it, to reach the cylinders of 
the engine. 

There are several good German designs, of which the Daimler, 
Fig. 116, is typical. 



Another type illustrative of German practice is the Benz. The 
carbureter from this car is shown in Fig. 117, in which the early 
connections of Maybach may be clearly traced. This is apparent in 
the rotary piston throttle, the shape and action of the float, the hand 
regulation of the fuel inlet opening, and many other small details. 

Double=Nozzle Type. A distinctive design of two connections 
leading into the vaporization chamber is the Zenith (French) car¬ 
bureter, a diagrammatic sketch being shown in Fig. 118. This is but 
a modification, in a way, of the Venturi plan, for the latter shape 
is actually used for the vaporizing chamber. The new idea consists 
in leading into this mixing chamber, not one but two tubes. Of these, 
one is the ordinary spray nozzle and does not differ from that used on 


308 





































GASOLINE AUTOMOBILES 


149 


hundreds of other devices. The second, however, is very different 
and, while leading into the same mixing chamber, does so through the 
medium of a secondary chamber or standpipe, to which the suction of 
the engine has access. If this suction is strong, more gasoline is 
drawn into the secondary chamber, from which it may enter the 
spraying zone. 

The ordinary nozzle is of an exact size and, consequently, can 
pass only a certain amount of fuel, always at the same speed. With 
the additional nozzle, this does not hold and, being of large diameter 
(comparatively), the flow 
through it depends wholly 
upon the engine suction, 
which varies at all speeds, 
often at the same speed 
upon different occasions. 

A Swiss design em¬ 
bodying the same prin¬ 
ciple but carried out in a 
different way is shown in 
Fig. 119. This is a design 
of Saurer, of Arbon, the 
designer of the Saurer and 
Safir trucks and pleasure 
cars. The peculiarity lies 
in the two standpipes A 
and B, one of which may 
be cut off by the action 
of the flap throttle valve 

C. This latter is operated by the demands of the motor, consequently 
when the need for fuel is greatest, it stands vertically so that both 
fuel standpipes or nozzles are supplying fuel. 

As shown in the figure, but one standpipe A is working, but as soon 
as the motor’s demands increase, the suction will draw the flap throttle 
valve C out of its inclined position, and then standpipe B will begin to 
furnish gasoline to the vaporizing chamber in addition to standpipe A. 
When the demand is greatest, both nozzles are supplying the full 
amount of gasoline, and the flap is standing vertically. Its action is 
partially restricted by a wedge attached to the throttle valve stem. 



Fig. 118. Zenith Carbureter 


309 













150 


GASOLINE AUTOMOBILES 


A notable new two-jet type of carbureter, which is practically a 
double device, one part for ordinary use and the other added for 
sudden spurts, hills, etc., is’ used on the Locomobile, Fig. 120. 

Use of By=Pass. This matter of two standpipes has a parallel 
in the use of a by-pass, so-called, around the usual mixing chamber. 
On some carbureters this is made so as to allow easy starting, the 
thought being that when suction is applied to the carbureter by 
cranking, with the throttle closed, practically pure gasoline vapor will 
be drawn through the by-pass. This will start the engine after 
which, as the throttle is opened gradually, its movement cuts off the 

by-pass, until at medium speeds 
it is out of use entirely. The same 
thing applies to the use of a sec¬ 
ondary tube or standpipe for low- 
speed running, as in the Ford, 
shown previously, and in the 
Browne and others to follow. 

A by-pass of a separate 
nature is made use of for starting 
and priming purposes; this con¬ 
sists of a small separate tank of 
gasoline attached to the dash¬ 
board under the hood, with a 
valve running through to the 
driver’s side for turning on the 
supply. This is connected into 
the inlet manifold above the car¬ 
bureter by means of a special 
When it is desired to start the 
motor, it is primed with this device by simply turning on the 
supply. Some gasoline flows into the manifold, and after waiting 
a few seconds for it to vaporize, the motor is cranked over sharply, 
when a start is almost certain. This has the advantage of simplicity, 
accessibility, and low cost. In addition, it is economical of time as 
compared with lifting the hood to prime each cylinder separately. 

Browne Carbureter, of Uniform Size and Simple Adjustment. 
An entirely new idea in carburetion has been produced in the Browne 
carbureter, which is so designed that but one size is needed for the 



Fig. 119. Saurer (Swiss) Carbureter with 
Two Standpipes 


pipe tapped into the manifold. 


310 























GASOLINE AUTOMOBILES 


151 


entire range of motors from the largest to the smallest—two-cycle as 
well as four-cycle—and regardless of the number of cylinders. This 
is done by having the actual walls of the mixing chamber of a Venturi 
shape and in the form of a removable bushing, which the maker fits 
to the size (cubical capacity) of the motor. In addition, a bushing 
which governs the entrance of the auxiliary air is sized and shaped 



Fig. 120. Locomobile Two-Jet Carbureter 


for the cubic contents of the motor, while the flange is of the screwed- 
on type so that it can be made of a size to fit the motor. 

Beyond this radical departure, the Browne device shows another 
equally startling innovation. It has but one adjustment—the 
setting of the needle valve for proper fuel supply—and this, once set 
correctly, need never be changed for altitude or temperature. 

Construction. To explain the construction which allows of these 
great departures from ordinary practice, refer to Figs. 121 and 122, 


311 

































































Fig. 121. Section Showing the Construction of the Browne Carbureter 

small, insuring sufficient velocities at very low speeds to atomize 
the fuel. Two factors make up the injecting force on the fuel 
nozzle—the vacuum created by the engine suction and the velocity 
of air flow. Both of these are made to act upon the air valve E in 
this device by introducing the vacuum chamber F beneath the valve, 
and connecting to the vaporizing chamber by the opening H. In 
this a ball G serves as a valve. 


152 GASOLINE AUTOMOBILES 

the former showing a section on the center line and the latter an 
external view, but taken from the opposite side to that of Fig. 121. In 
Fig. 121 the fuel flows from a float chamber P of conventional design 
to the fuel nozzle by a passage not shown, but indicated in Fig. 
122. This is located in the throat of a Venturi passage V with a 
30-degree approach and a 7-degree discharge. The area here is 


312 


















GASOLINE AUTOMOBILES 


153 


In this manner, the air at any velocity of flow is transmitted to 
the. air valve, which through its position influences the amount of 
auxiliary air admitted. In the upper part of the carbureter, it will 
be noted that the auxiliary air flows in through the openings on the 
under side of the cover B, over the curved bushing C, and past the 
upper edges of the air valve E, to the mixing chamber Y. Obviously, 
any engine suction is transmitted to E, so that both forces working 
on the nozzle work on the air valve as well. In the air valve, which 
is made of aluminum, the curve of the bushing C is so constructed as 
to admit always the right amount of air, but with varying velocities. 
This is an important 
feature, for air valves 
generally are considered 
to open too far at high 
speeds. What actually 
happens is that the ve¬ 
locity is reduced too low 
and not enough fuel 
flows. As pointed out 
above, this device, by in¬ 
creasing the velocity of 
inflow, overcomes this 
defect. 

Water-J acketing . 

Water-jacketing, on this 
device, is a necessity to 
proper and continuous operation, hence liberal jackets are sup¬ 
plied, W in Fig. 121 indicating the hot water inlet, and W' in 
Fig. 122, its outlet. In addition, pre-heating of the primary air is 
considered a necessity, so a large hot-air horn is supplied at K for 
the attachment of a hot-air connection to the exhaust manifold. 
This heating is very carefully set down by the makers of this device 
as follows: The temperature of circulating water is practically 
constant, summer and winter. Such heat supplied to the carbureter 
gives two things—a constant temperature of the fuel passing the 
nozzle, which is necessary in order to get accuracy of flow, and a 
rapid evaporation of any fuel that is deposited as a film upon the 
hot walls, thus increasing the economy of the device. 






154 


GASOLINE AUTOMOBILES 


Kerosene and Heavy Fuel Carbureters. As has been mentioned 
several times previously, and explained elsewhere in detail, the 
lighter, more volatile grades of gasoline are not available in sufficient 
quantities to supply the present demand. Consequently, the fuel 
now carries a considerable quantity of what was formerly sold as 
kerosene, and under other names. At that, the fuel sold is still 
much lighter than kerosene—of which tremendous quantities are 
available—as well as other heavy fuels, notably benzole in England, 
where kerosene is called paraffin. To develop a carbureter which 
would handle these cheaper but heavier and more available fuels 

has been the aim of many in¬ 
ventors, and a vexing problem 
for carbureter manufacturers. 

Holley Type. A firm 
which has devoted much time 
and study to this problem, 
the Holley Company, has de¬ 
veloped the device shown in 
Fig. 123. While this is not 
offered as perfect, even by its 
maker who is still working on 
this problem, it has been found 
to do these things: Cut the 
fuel cost over 50 per cent; in¬ 
crease the power 5 to 8 per 
cent; save almost one-half of 
the engine lubricant; give less 
spark-plug trouble and less 
carbonizing; and give a greater 
mileage to the gallon. In doing these things, it has these deficiencies: 
Requires the use of gasoline for starting; and necessitates a material 
reduction in compression pressures. 

As shown in Fig. 123, and applied to a motor in Fig. 124, the 
float chamber is standard. Exhaust gases enter at F, passing around 
the two vaporizing tubes R and L, and out at S. The primary air 
enters at I, is heated by the exhaust, and at low speeds flows up 
through the mixer tube R. This is supplied by the nozzle Q, and by 
noting the constructions at its upper end, it will be seen that this 



314 

























































GASOLINE AUTOMOBILES 


155 


works only until the butterfly B is opened, when nozzle K comes into 
action. The tube L for the latter is corrugated to get the greatest 
possible heated surface for its length. Fig. 124 shows its applica¬ 
tion to a motor, K being the exhaust connection to the kerosene 
carbureter A, with B, the gasoline vaporizer for starting, and C and 
D its connection into the inlet manifold. Lever F on the dash con¬ 
trols this, it being shut off after starting. The usual throttle connec¬ 
tion to lever H has another connection to lever J which operates an 
exhaust throttle, the idea being to deflect all the gases to the kero¬ 
sene carbureter at low speeds, but as the throttle is opened and the 
engine speeds up, producing more heat, less exhaust gas goes to the 
vaporizer. In testing out 
this device, the maker 
found three necessities, 
namely: Shortest possi¬ 
ble kerosene manifold; 
shortest possible exhaust 
heating pipe connection 
( K ); and shortest possi¬ 
ble gasoline connecting 
tube ( C ). 

Foreign Kerosene 
Carbureters. A large num¬ 
ber of firms in different 
parts of the world have 
worked on this problem of kerosene vaporization. In Germany, the 
following have done so, and in this have been obliged each to develop 
his own vaporizer: Daimler; Swiderski; Maurer; Adler; Sleipner 
(boats mostly); Deutz; Banki; Neckarsulmer (motorcycle); Koerting 
(fuel injection); Hamper; Diesel (fuel injection); Capitaine (boats 
mostly); Gardner; Dufaux (Swiss motorcycle); and others. Space 
prevents a description of these, the list being given simply to show 
that kerosene as a fuel has attracted wide attention. 

In France the same is true, the Aster device, for instance, having 
been so very successful that it is now made under license in both 
England and Germany. 

In England the Binks with two jets is designed to use 20 per 
cent gasoline and 80 per cent kerosene after starting; the Hamilton 



Fig. 124. Method of Applying Holley Kerosene Car¬ 
bureter to Engine, with Exhaust Piping, etc. 


315 



























156 


GASOLINE AUTOMOBILES 


Bi-fuel has two float chambers, two nozzles, and other duplicate 
features. This is designed for a 44 gasoline (petrol) and 56 kerosene 
(paraffin) mixture; on such a mixture, a test of a bus engine showed 
equal (rated) power at 890 r.p.m.; 1 horsepower more at 1050; almost 
3 more at 1275; 100 more r.p.m. at the highest speed and 3 horse¬ 
power more maximum output; Kellaway has two fuel leads, but these 
use a common jet; Morris uses forced feed with a constant air pressure 

of 4 pounds per square 
inch on the fuel tank, this 
being supposed to mini¬ 
mize variations in fuel 
flow, and thus, as pointed 
out in the description 
of the Browne, minimize 
variations in the output; 
Southey ignites part of 
the fuel to create heat 
with which to vaporize 
the balance, delivering to 
the cylinders a fixed gas 
which is heated; the 
Edwards has been de¬ 
scribed ; and in the Notax 
the fuel spray, as it enters 
the vaporizing chamber, 
is forced to strike the 
lower hot surface of the 
exhaust gas passage, the 
latter not only encircling 
the chamber but having a passage right through the middle of it; in the 
G. C. (English and American) the vaporizer complete replaces both 
carbureter and muffler, the latter being constructed especially for 
utilizing all the heat of the exhaust gases to vaporize the kerosene, 
which then is led up to the engine, and auxiliary air added just before 
entering the manifold. This has a separate small gasoline carbu¬ 
reter for starting and a special float chamber for the kerosene. In 
America, the Knox employs an arrangement in which a gasoline 
by-pass around the entire carbureter is used for starting, while the 



Fig. 125. Diagrammatic Section through the Harroun 
Kerosene Carbureter, Snowing Its Action 


316 




















GASOLINE AUTOMOBILES 


157 


exhaust heating concerns the fuel at the bottom of the device only; 
the Secor type is used on the Rumely tractors. The Hart-Parr 
Tractor Company, and a number of other builders of tractor, marine, 
and stationary engines have all been more or less successful in vapor¬ 
izing kerosene so as to use it advantageously. 

Harroun Kerosene Carbureter. To present a couple of successful 
American devices, Fig, 125 shows a diagrammatic section of the 
Harroun carbureter and Fig. 126 the Senrab carbureter. The 
Harroun device was used on the Henderson cars which made the 
trip to the Pacific Coast, and showed a cost for the fuel consumption 
for the 4015 miles of but $29.11 on one and $32.50 for the heavier 
six-cylinder model; this figured out almost 18 miles on a gallon. 
Other tests made on Marmon and Overland cars with this device 
showed 11 per cent greater mileage on kerosene than on gasoline 
(22.2 against 20). In a run with an Overland car from Chicago to 
Indianapolis without special preparation, the 224 miles was covered 
at an average speed of 20 m.p.h., the fuel consumption of 13 gallons 
of kerosene figuring out to 17i miles a gallon. Later, this carbureter 
and fuel were used on one of the Maxwell cars which went through 
the 500-mile race at Indianapolis and finished ninth. 

Referring to the figure, it will be noticed first, that the manifold 
is not jacketed, that the fuel is not pre-heated, also that the auxiliary 
air is not pre-heated (although heat is used, the mixture is after¬ 
wards cooled by the addition of cold air), and that the auxiliary air 
valve automatically operates the spray needle to control the flow of 
fuel, this latter being adjusted from the dashboard, thus reducing 
the adjustments to this one. To go into details, refer to Fig. 125. 
Here the fuel is seen to enter the usual float chamber from below, 
the fuel being atomized in a Venturi-shaped chamber by a stand¬ 
pipe J which is erected in its center. The air for this atomization 
enters from below, being drawn up through the enlarged-surface 
vaporizing chamber Z), and heated in its passage by the exhaust. 

Down the center of this chamber extends the needle B, its upper 
end being connected to the lever, which carries at its other end the 
air valve E. As the increased suction depresses this, the needle is 
drawn up, and more fuel admitted; similarly, when less suction is 
present, the spring and the weight of the needle act to shut off the 
flow of the fuel. This maker also advises lowered compression. 


317 


158 


GASOLINE AUTOMOBILES 


Senrab Carbureter. In the Senrab device, pictured in section in 
Fig. 126, several novel ideas are incorporated with resulting sim¬ 
plicity. The fuel enters the usual float chamber A , whence it 
passes through a thin flat passage B , entirely surrounded by heated 
exhaust gases which enter at C. In addition, the float is a very 
close fit in its chamber, hence the heating effect there is considerable. 
Entering the central standpipe D, the fuel is atomized by the needle 

E and in passing out through 
the series of small holes into 
the Venturi-shaped mixing 
chamber F. In the latter, it 
is mixed with the primary 
air entering at the bottom 
through Gj while higher up in 
the vaporizing chamber it is 
diluted by the auxiliary air 
entering through the ports H. 
Thence, it passes to the out¬ 
let N. The auxiliary air 
opening is governed by the 
movement of the piston I, 
which may be moved up or 
down permanently on the 
threaded stem J. This is 
effected by turning the knurled 
knob K , the smaller one L 
controlling the needle posi¬ 
tion. All these are moved 
up and down by the opera¬ 
tion of the lever M. For 
starting, gasoline can be ad¬ 
mitted directly into the Venturi chamber F by means of a side 
connection not shown. 

NEWEST CARBURETER FEATURES 

Nature of New Developments. Horizontal Carbureter Outlets. 
Among the newest carbureter features are some which have 
worked themselves out naturally, and others which have been 



Fig. 126. Section through the Senrab 
Kerosene Carbureter 











































GASOLINE AUTOMOBILES 


159 


forced by changes in engine design, in fuel quality, etc. Thus the 
tendency toward block motors and with it the tendency toward neat 
lines and simplicity, 
has brought forth 
general simplification 
of inlet pipes, a fairly | 
general elimination of ^ 
them, and a fairly wide 
use of horizontal car¬ 
bureter outlets. The 
latter has affected car¬ 
bureters by requiring 
a shorter, more com¬ 
pact instrument, with 
a side outlet and, in 
addition, a vaporizing 
arrangement which 
will produce tolerably 
complete vaporization 
in a comparatively 
short distance. To a 
certain extent, this 
horizontal carbureter 
tendency has modified 
existing practice in 
nozzles, Venturis, in¬ 
terior areas and ar¬ 
rangements, etc. 

Effect of Heavier 
Fuels . The growing 
realization by carbu- 
re ter manufacturers 
that increased use of 
heavier fuels is inevi¬ 
table, has brought 
forth much worthy effort in the way of vaporizing them. This 
has temporarily set aside the kerosene and other heavy-fuel 
vaporizers. However, as the fuel is bound to become heavier and 




























































160 


GASOLINE AUTOMOBILES 


heavier, on account of the excessive demands for gasoline it is only 
a question of a year or so before kerosene and distillate vaporizers 
will be agitated again. 

Effect of Vacuum Feeds. The wide use of vacuum feeding 
devices, combined with the tendency mentioned above, to clean 
and simplify, has caused a much higher mounting of carbureters. 
This has always been desirable but hitherto it has not been possible. 
The vacuum feed for the gasoline supply has made this change 
possible, while the cleaning process and simplification actually 
forced it. 

Effect of Motor Changes. The high-speed form of motor now so 
generally being adopted has had a big influence, as have also the 
multicylinder forms, both creating a demand for greater accelera¬ 
tion. Similarly, starting devices have forced the use of a carbureter 
modification by which instant starting is possible. These require¬ 
ments have called for new designs, smaller and lighter parts, more 
nearly complete automatic actions to uncover large air ports, as well 
as other improvements. 

Double Carbureters for Multicylinder Motors. While many 
eight- and twelve-cylinder motors have but a larger-sized plain car¬ 
bureter, the better forms have a double device, each half supplying 
a group of cylinders and, except for a common fuel supply pipe, 
being entirely separate and distinct from the other. A notable 
example of this is the Zenith, shown in Fig. 127. Each set of cylin¬ 
ders has its own suction-actuated nozzle and its own independent 
nozzle, just as the single instrument shown in Fig. 118 has. This 
device has shown its worth in actual use, having been very successful 
in aeroplane work on eight-cylinder and twelve-cylinder motors, 
and also on a number of the better eight- and twelve-cylinder 
motor cars. 

Multiple Nozzle Carbureters. Another development brought 
about by this demand for rapid acceleration coupled with great 
maximum capacity, has been the swing toward multiple nozzles. 
As has been pointed out on previous pages, there are a number of 
carbureters now with two nozzles. There are besides several designs 
with triple nozzles (notably the Greuter, used on the Singer car), 
and one with a very large number of nozzles, Fig. 128. The latter, 
originally developed on the Pacific Coast to handle extra heavy 


GASOLINE AUTOMOBILES 


161 



321 


Fig. 128. Section through the Master Carbureter, Which Is a Multiple Nozzle Form and Handles Heavy Fuels Well 
Courtesy of Master Carbureter Company, Detroit, Michigan 







































































































162 


GASOLINE AUTOMOBILES 


fuels, is called the “Master”, and is made by the Master Carbureter 
Company, Detroit, Michigan. It has 14 or 15 nozzles, each of 
which is uncovered and comes into play with the rotation of the 
throttle as the demand for gas varies. The device, as the figure 
shows, is unusually simple, and its success in racing work, where the 
demands are abnormal, has proved all the claims made for it. 

CARBURETER TROUBLES 

Engine Should Start on the First Turn. In starting a car or any 

engine, whether located in a car or not, everything should be inspected 
so as to know if all is right before attempting a start. With the 
novice, this is somewhat of a task, but to the old hand it is so much 
of a routine task that he does it unconsciously. If all conditions are 
right, the carbureter is primed and the engine will start on the first 
turn of the crank. If it does not do so, there is a source of trouble 
which must be remedied first and it is useless to continue cranking. 
This may lie in the fuel system itself, but exterior to the vaporizer, 
or it may be in the ignition apparatus. It is well in a case of this 
sort to start with the gasoline tank and follow the fuel through each 
step until it apparently reaches the combustion chamber in the form 
of a properly proportioned mixture of gasoline and air. 

To start with the tank—is there enough fuel in it not only for 
starting purposes, but enough to allow of making the proposed trip? 
This is readily ascertained by unscrewing the filler cap and inserting 
a measuring stick. For the purpose a graduated rule is good, but 
not necessary; any stick or small branch of a tree will answer, or, 
lacking all these, a piece of wire can be used. A string tied to a very 
small weight will also do if withdrawn quickly and measured at once. 

Having verified the presence of fuel, the next question is: Does 
it reach the vaporizer as it should? Nearly all carbureters have a 
drain cock at the lowest point. Open this and if fuel flows out in a 
steady stream you may be sure that the pipe from the tank up to this 
point is not clogged. In case the carbureter does not have a drain 
cock, the same result can be effected by holding the primer down for 
a long time, when the gasoline will overflow through the air inlet. 

In either case, if there is no sign of gasoline when the tank 
contains plenty, it is apparent that the feed pipe is clogged and the 
method of procedure is as follows: Shut off the cock below the 


GASOLINE AUTOMOBILES 


163 


tank so that none of the previous liquid can escape, then drain off 
the carbureter and pipe into a handy pail. Next open the union 
below the cock in the feed line and the one at the other end of the 
same pipe. At both places look for obstruction. Then clean the 
pipe out thoroughly, using flowing water, a piece of wire, or other 
means which are available at the time. 

Gasoline Strainer a Source of Trouble. Finding nothing here, 
it will be necessary to search. Look in the strainer of the carbureter 
to make sure that the flow is not stopped there by the accumulation 
of dirt and grit, filtered out of the fuel. The strainer should be 
cleaned often, but like many other dirty jobs is postponed from 
time to time. 

Should this source of trouble prove “not guilty” the carbureter 
itself becomes an object of suspicion. Is the float jammed down 
upon its seat or are there obstructions 
which prevent the flow of fluid? Is the 
float punctured, or has one of the sol¬ 
dered joints, if a metal one, opened, or 
is it fuel-soaked, if cork? 

Bent Needle Valve Stem. To at¬ 
tend to this sort of trouble, disconnect 
the priming arrangement, take the cover 
off of the float chamber (it usually is 
screwed on with a right-hand thread), 
and take the float out. An examination 
of the float, Fig. 129, will disclose whether 
it is at fault in any of the above-men¬ 
tioned ways, all of which are comparatively easy to fix. If the float 
was jammed down, perhaps by priming, the act of taking it out will 
cure, provided that the stem of the float is not bent and the 
needle valve or its seat not injured. If the seat is scored it should be 
ground-in just like any other valve, using oil and fine emery. A fuel- 
soaked cork should be thrown away if another is at hand to replace 
it, but if not, the cork float should be moved in its position on the 
stem so that it sets higher in the liquid. In other words, move the 
cork a sufficient amount to compensate for its loss of buoyancy. 

In cases of a punctured metal float, or of loose solder, the only 
real remedy in either case is to resolder. It usually happens that a 





































164 


GASOLINE AUTOMOBILES 


soldering outfit is not available out on the road and some form of 
makeshift will be necessary to allow of reaching a place where a 
soldering iron may be had. If the puncture is on the bottom, it is 
sometimes possible to accomplish this by inverting the float so that 
the hole comes at the top where the gasoline seldom reaches. If the 
flow be reduced to make sure of this, it is possible to reach a place 
where a soldering iron may be procured. 

A remedy which might be‘ tried in an extreme case of this sort is 
to fill the float to make it heavy, so that it will have a tendency to 
sink. Then take a small-diameter spring, cut off a short piece of it 
and place it in the float chamber so that it opposes the sinking action 
of the now-heavy float. By carefully determining the length, and 
thus the strength of this spring, the same action is obtained as would 
be had if the float were working all right. Of course, if the entrance 
of the liquid fuel is such that the sinking of the heavy float tends to 
close rather than open the gasoline inlet, the spring would have to 
be on the bottom and fairly strong so as to oppose the action of grav¬ 
ity. But if the float works downward to open the gasoline passage, 
the spring will be at the bottom and very weak, simply being there 
to prevent an excessive flow. 

Throttle Loose on Shaft. Now the carbureter trouble has been 
reduced to a minimum. The remaining troubles might be centered 
in a clogged spraying nozzle. But this nozzle is readily removed, 
and with it the trouble, if that be the offending member. If the 
spray is proven O. K., the throttle is ready for attention. If of the 
butterfly type, it may have become loose on its shaft, or, what is the 
same thing, the operating lever may be loose. In either case the 
shape and weight are such that it would swing into such a position 
as to cut off the entrance of gas to the inlet pipe and thus to the 
cylinder. If the throttle is of the circular sliding or piston form it 
may not be connected to the throttle rod, but is stuck in such a 
position as to prevent the passage of gas. This sometimes happens 
when running, and then, apparently, closing the throttle does not 
stop the engine. The writer had this happen to him once at a time 
when it was absolutely necessary to stop. The only way that trouble 
was averted was by the instantaneous closing off of the switch and 
the hasty application of the brakes. 

The last hope of finding trouble in the carbureter system rests 


324 




GASOLINE AUTOMOBILES 


165 


with the inlet pipe. If the source of the trouble is not found else¬ 
where, take this off in search of misplaced waste or similar sub¬ 
stances. The size of the pipe is such that anything in it large enough 
to cause trouble may be instantly seen and removed. The only 
exception to this is a small hole in the inlet pipe casting, which will 
not only cause trouble with the mixture at all times, but is also very 
hard to find, particularly if it happens to be of very small diameter, 
caused by a single grain of sand, for instance. 

The valve or cock controlling the flow of liquid from the tank 
should be examined frequently and care be taken to keep it in good 
shape. It must act hard and must be tight, so that no gasoline flows 
when it is supposed to be shut off. The reason for having it act hard 
is to prevent it jiggling shut during a long run, which results in the 
engine slowing down and stopping without any apparent reason 
until the tank is looked at, when the supply is found to be shut off. 
A method of fixing it—which, in general, is not to be recommended— 
is to open the cock and then hammer the handle so as to jam it 
tight against the seat, but in the open position. This makeshift will 
answer until a place is reached where the taper seat can be reground 
or tightened in place, if that is what it needs. In case the driver 
does not wish to do this, and the cock is of the two-way type—open 
when the handle is parallel to the axis of the pipe—it may be tied m 
the open position by passing a cord around the cock and pipe. 

Carbureter Adjustment. In adjusting the carbureter the 
worker should remember that the correct proportion varies from 11 
to 14 parts of air to 1 of gasoline vapor. It is not always possible 
to measure the two in just this way, but the adjustment is provided 
for in the carbureter. The tendency in carbureter construction is 
toward simplification and fewer adjustments. 

Rayfield Gasoline Adjustments . In the Rayfield, for instance, 
the auxiliary air is automatic and cannot be adjusted, but there are 
two gasoline adjustments. In both of them the arrangement is 
such that the screw heads are turned to the right to give a richer 
mixture. The first adjustment, for low speed, is as follows: With 
the throttle closed and the dash control lever down, close the nozzle 
needle by turning to the left until the small block slightly leaves the 
cam; then, turn to the right about three complete turns; open the 
throttle not more than one-quarter. This is the preliminary adjust- 


166 


GASOLINE AUTOMOBILES 


ment. Start the motor, and after it has warmed up and is running 
well, throttle down to the lowest possible speed. Turn the low- 
speed screw to the left slowly but steadily until the motor slows to a 
marked extent and shows signs of stopping. Turn back to the right 
a couple of notches, and if the motor steadies down and idles 
smoothly, lock it in that position. 

The high-speed adjustment is made as follows: Advance the 
spark about one-quarter, then pull the throttle open quickly. Should 
the motor backfire, that indicates a lean mixture, which is corrected 
by turning the high-speed adjusting screw to the right, one notch 
at a time, until the throttle can be opened quickly to the full extent 
without back-firing. If choking or loading occurs when the throttle 
is opened wide, turn the screw back to the left a notch or so. Lock 
this adjustment when it has been made. 

In making carbureter adjustments, always remember to make 
them with the motor hot. A good plan is not to make any adjust¬ 
ments of this kind until after the motor has been running for an hour. 

Tool for Carbureter Nozzles. Many carbureter nozzles are made 
with a screw driver slot to facilitate their removal. It will soon be 
found, however, that the screw driver is not so easy to use on these 
as a home-made tool. One useful form consists of a bar of J-inch 
steel bar stock bent into the form of an L, the short end being flat¬ 
tened down into a screw driver thickness and hardened. 

Starving at High Speeds. Many times a motorist will experience 
the phenomenon known as starving at high speeds—that is, his 
motor will give better power and run faster with the throttle partly 
closed than when wide open. This is caused by the auxiliary air 
valve not opening sufficiently to admit the large quantity of air 
needed at the widest throttle opening. The mixture, therefore, 
becomes too rich and the motor starves. 

This trouble points out the fact that auxiliary air-valve adjust¬ 
ment was not covered in adjusting the carbureter just described and 
this was because the Rayfield does not have an auxiliary air-valve 
adjustment. This valve usually has an outside spring, the tension 
of which is controlled by a milled nut, also on the outside. Then, 
when it is desired to make a change in the mixture, the nut is turned, 
altering the tension of the spring, and thus, altering the lift of the 
air valve; in this way the proper amount of air is admitted. To 


326 


GASOLINE AUTOMOBILES 


167 


admit more air, the nut is backed off in order to weaken the tension 
and thus allow the air valve to open wider. To admit less air, the 
spring tension must be increased so that the air valve cannot open 
quite so far, or stay open so long. 

Adjustments for Heating Water and Air Supply. On a large 
number of carbureters there are two more adjustments — the heat¬ 
ing of the water and the heating of the air. The general run of 
carbureters now are water-jacketed to help vaporize the heavy 
fuels, and during warm weather this may supply too much heat. 
For this reason, a cock is generally fitted to the hot-water line which 
will allow partial as well as total closure. 

Similarly, hot air is supplied to almost all carbureters to vapor¬ 
ize the heavy fuels more quickly, a necessity if rapid acceleration, 
quick getaways, and other present-day demands are satisfied. In 
order to vary the hot air according to the weather or to cut it off 
entirely, some kind of a shutter is provided which can be locked in 
any position. When the days begin to grow warm late in the 
spring, the shutter is partly closed; during the heat of mid-summer, 
it is dosed completely, and sometimes the connection with the 
exhaust manifold for heating the air is entirely removed from the 
car; when the temperatures begin to go down, the shutter is opened 
again, and in cold weather it is entirely open and as much heat as 
possible is supplied the carbureter. 

FUEL SUPPLY 

For storage of the fuel required for the propulsion of a car, 
and to feed the fuel to the carbureter, many different systems are 
in use. 

Tank Placing. In automobiles the gasoline tanks are generally 
placed under the front or rear seats, or under the frame at the rear. 
In many types of runabouts and roadsters the tank is placed above 
the frame at the rear. 

Fuel Feeding. When the tank is at the rear or when it is under 
the front or rear seat, no special provision is necessary, under ordinary 
circumstances, to insure a positive flow of the liquid fuel to the 
carbureter. 

Gravity. With the tanks placed high, the gasoline can be 
depended upon to run down to the float chamber by gravity, except 


327 


168 


GASOLINE AUTOMOBILES 


that in mountainous districts it sometimes is found, in climbing very 
steep hills, that the angle becomes such that the fuel will not flow, 
expecially when the tanks are under or back of the rear seat, or when 
they are nearly empty. 

A means of getting around this difficulty is to place on the front 
of the dashboard, behind the engine and under the bonnet, a small 
auxiliary tank of one or two gallons’ capacity, from which there is a 
direct pipe leading to the carbureter. When the car is in a level 
position, this auxiliary tank fills automatically from the main tank, 
but a simple valve prevents the contents of the auxiliary tank from 
running back when the machine is tilted up. In this way a sufficient 
supply for 15 or 20 miles running is placed in a position to reach the 
carbureter under any possible road condition. 

Air Pressure . With the tanks placed low, whether under the 
frame or above it, it is necessary to feed the fuel to the carbureter 
by more positive means than gravity. One of the commonest sys¬ 
tems involves pumping a low air pressure into the tank above the fuel, 
so that this pressure forces the liquid out regardless of the relative 
heights of tank and carbureter. Ordinarily, a small hand pump 
is sufficient to provide such air pressure, though in modern auto¬ 
mobiles equipped with compressed-air starting devices, or com¬ 
pressed-air tanks for filling the tires, provision can readily be made 
for supplying the tanks with air from these sources for the purpose 
of feeding the fuel. 

Exhaust Pressure. A system of providing pressure in the fuel 
tanks that is much used, though not so highly regarded as in the past, 
is to tap the exhaust piping and to take from the connection a pipe 
line that permits the entry of a certain amount of the exhaust gases 
into the fuel tank. A simple automatic valve controls the pressure 
and shuts off the admission of gas when the pressure rises above the 
very low maximum required. In a system of this character there 
is no possible danger of fire, not only because the exhaust gas is 
very quickly cooled in passing through a length of small piping, 
but also because the contents of a gasoline tank are ordinarily not 
ignitible, because of the lack of any air to support the combustion. 

Sooting up of the automatic valve is the commonest trouble 
with this system. 

New Vacuum Feed Device. The many troubles incident to the 


328 


GASOLINE AUTOMOBILES 


169 


use of the rear tank location with pressure feed have brought about 
the production of a new device, which is called the Stewart vacuum 
feed. This is a small compact circular unit, which is placed on the 
dash under the hood, for use with a rear tank, and when so used, 
eliminates the pressure feed. A sectional drawing of this is shown in 
Fig. 130. It may be described as follows: There are three connec¬ 
tions at the top, one to the gasoline tank, one to the intake manifold, 
and one to the air vent. Through the medium 
of the intake manifold connection, the motor 
suction is communicated to the tank, for that 
is what the device amounts to. This produces 
a vacuum, and opens the valve connecting 
with the gasoline tank. That, as well as the 
connecting pipe line, being air-tight, gasoline 
is drawn in to fill the vacuum space, flowing 
into the upper chamber, with which the gaso¬ 
line tank communicates. 

This has a valve connection to the lower 
chamber operated by means of a float, this in 
turn being controlled by the intake manifold 
suction, through the medium of the system 
of levers. By it, the lower chamber is kept 
filled to a fairly high level, whence feed to the 
carbureter is by gravity. The system thus 
does away with all the troubles of the pres¬ 
sure system, at the same time allowing of the 
accessible and advantageous rear tank loca¬ 
tion. It is placed as high as possible, on the 
inside of the dash under the hood, hence there 

Fig. 130. Section through the . . .i •, r* 1 „ 

Stewart Vacuum Gasoline jg never any trouble with the gravity teed even 

Feed Device _ T , . . 

on the steepest hill. In one test, this vacuum 
feed device increased the mileage of the car per gallon of fuel, by 
more than 22 per cent. 

Fuel Pumps. In a few automobiles, instead of the use of a 
carbureter with a float chamber, the expedient has been successfully 
employed of providing a small gasoline pump, constantly driven bj 
the engine as long as it is running, and so pumping an excess of gaso¬ 
line from the tank through the carbureter chamber, whence the sur- 



329 














170 


GASOLINE AUTOMOBILES 


plus is returned to the tank through an overflow, placed at a certain 
height so as to maintain constantly a proper level. 

Piping and Connections. In arranging the piping system for 
the fuel supply of a gasoline automobile, the first essential is to use a 
soft brass or copper tubing that can be depended upon not to break 
from the vibration to which it is subjected. 

As a further safeguard against breakage, and to allow alterations 
in the relative positions of different parts, due either to the straining 
of the machine while it is in use or to a change of adjustments when 
it is disassembled or reassembled, loops or coils introduced at proper 
points in a pipe line are of great advantage. 

Stopcocks close to the tanks are an excellent, safeguard against 
fire, since they permit the shutting off of fuel supply in the case of 
any breaks in the line. Such safeguards always should be provided. 

With reference to the pressure system of fuel feed, there is hardly 
any limit to the precautions which must be taken to avoid leaks. The 
smallest leak puts the system out of commission, for as soon as the 
pressure leaks down to a point where the fuel will not rise to the car¬ 
bureter, the engine cannot be operated until the leak is found and 
fixed. To avoid this, many drivers go over all joints frequently and 
likewise replace all old packing. In addition, they wipe the joints 
with soap to prevent leakage, and then cover them on the outside 
with tire tape or similar flexible material which can be wound on in 
such a way as to stay permanently. The rapid adoption of the 
Stewart device since it was brought out in 1914 shows better than 
anything else how troublesome was the pressure feed system. Sta¬ 
tistics for 1914 cars showed that in 237 different models, 109 had the 
gravity tank under the seat, and 31 in the cowl, this making 140 
with gravity feed, leaving 97 with the rear pressure tank location. 
Similar statistics for 1915 show 52 per cent in favor of the rear 
tank location, while 1916 shows almost 66 per cent rear location, 54 
per cent being vacuum fed. 

Reserve Tanks. To guard against the annoying mishap of 
having the gasoline give out while an automobile is in use, perhaps 
remote from any source of supply, many cars are now provided with 
reserve tanks, in which there are held back one or two gallons of the 
motive fluid, so that this reserve cannot be used except when it is 
fed into the system through the deliberate intent of the operator. 


330 



GASOLINE AUTOMOBILES 


171 


In its simplest and one of its best forms, a reserve tank takes 
the shape of a partitioned-off portion of the main tank, into which 
the gasoline automatically flows through an opening at the top when 
the tank is filled, but from which it cannot pass to the carbureter— 
usually by way of the main tank—until a special valve at the bottom 
of it is manually opened. 

A later and even more simple provision is the use for the gasoline 
tank of a three-way outlet cock which has a fairly long extension up 
into the tank. The extension tube is of course open at the top and in 
addition has a hole near the bottom of the tank which communicates 
through a branch tube with the third way of the cock. When the 
outlet cock is set for normal flow, the fuel feeds until the level reaches 
the top of the extension, at which point it stops flowing. This is the 
warning to the driver that his fuel is low. Then all he has to do 
is to turn the outlet cock to the other position, thus allowing the fuel 
to feed from the bottom hole of the extension tube. The remainder 
of the fuel, that is, the amount represented by the difference in level 
between the top and bottom of the extension tube, will carry the car 
to the next fuel station. 

Fuel Gages. The matter of depth and quantity indicators has 
received much attention in the last few years, with the result that 
practically all new cars have some form of gage on or in the fuel 
system. On rear pressure tanks, it is usually located on the tank, so 
the driver must go to the rear of the car to see how much fuel he has 
left, but on cowl tanks or those located under the seat, it is possible 
to have the gage set on the instrument board or the dash, as the case 
may be, thus keeping it in plain sight. Practically all the gages give 
indications in gallons and fractions, so that with the gasoline gage and 
odometer in front of him, and knowing how many miles he averages 
to the gallon of fuel, no driver need worry about having gas. He can 
readily figure ahead and keep sufficient on hand for his needs. A 
device has been produced to give dashboard indication of rear tank 
capacities, but this is so complicated and expensive that it is little 
used. 

Fuel System Troubles and Repairs. Failure of Fuel to Flow 
from Fmll Gravity Tank. Many times the fuel will not flow from a 
gravity tank which is full. This may be because the air holes in the 
filler have been stopped up so that no air can enter. By cleaning 


331 


172 


GASOLINE AUTOMOBILES 


out the holes, if there are any, drilling some if there are not, or by 
loosening the filler, this can be remedied. For this reason, it is well 
not to use a gasket or washer on a gravity tank. On a pressure 
tank, just the reverse situation exists, and it is advisable to use a 
rubber or leather washer at the filler cap. 

Fuel Line Obstructed . Many times an obstruction in the fuel 
line will be found at a very low point or sharp bend, where dirt in 
the fuel has gradually collected until there was enough to cut off 
the flow. A good way out of such a difficulty is to close connections 
at the tank and at the carbureter, take the entire fuel line off, and 
blow it out with compressed air. This will clean it thoroughly. 

Lock on Fuel Line. The garage or repair man can insert a very 
efficient lock on any car by putting into the fuel line at a convenient 
point a shut-off cock which works with a removable key. These are 
readily obtained and any good workman can install one in a couple 
of hours. Many owners of cars would be glad of an efficient lock 
and would be willing to pay well for one. This one has the advantage 
of being simple, cheap, and effective. 


332 
















































































































VIEW FROM UNDERNEATH OF MARMON REAR AXLE AND TRANSMISSION 

Courtesy of Nordyke & Marmon Company, Indianapolis, Indiana 


CADILLAC HELICAL-BEVEL DRIVING GEAR AND PINION 

Courtesy of Cadillac Motor Company, Detroit, Michigan 










































GASOLINE AUTOMOBILES 

PART III 


CLUTCH 

Classification. Principal among the indispensable parts inter¬ 
vening between engine and road wheels, and one which may be a 
source of great joy or correspondingly great wrath, according to 
whether it be well or poorly designed and fitted, is the clutch. There 
are six forms into which clutches may be divided, although not all 
of them are in general use in the automobile. In general, only the 
first four are used on automobiles. These different forms are: 

(1) Cone clutches 

(2) Band or drum clutches 

(3) Expanding ring clutches 

(4) Disk and friction clutches 

(5) Hydraulic or fluid clutches 

(6) Magnetic or electric clutches 

The necessity for a clutch lies in the fact that the best results 
are obtained in an automobile engine when run at constant speed. 
Inasmuch as the speed of the car cannot, from the nature of its use, 
be constant, it requires some form of speed variator. This is the 
usual gear box or transmission, but in addition, there is the necessity 
of disconnecting this from the motor upon starting, since the engine 
cannot start under a load. There is also the necessity for disconnect¬ 
ing the two when it is desired to change from one speed to another 
either by way of an increase or a decrease. So, also, when one wishes 
to stop the car, there must be some form of disconnection. There 
are then three real and weighty reasons for having a clutch. 

Cone Clutch. Single Cone Type. This consists of two members, 
one fixed on the flywheel or other rotating part of the engine, the 
other fixed to the transmission shaft. The latter usually slides upon 
the shaft so as to allow engagement and disengagement. A spring 
holds the two together or apart, according to the type of clutch used. 



174 


GASOLINE AUTOMOBILES 


^Ten the smaller-diameter member is spoken of, it is usually called 
the male member, while the part of larger size is spoken of as the 
female member . 

The cone type is found to be made in two different varieties; 
the one in which the male member enters the female naturally at the 
open end is called the direct cone type. In the other form, the male 
is set within the structure of the female and is pressed outward 

toward the open end to 
engage it. This is called 
the inverted, or sometimes 
the reversed, cone clutch. 

A great disadvan¬ 
tage of the inverted form 
is that the spring must 
be carried between the 
two cones, which means 
that it is inside where 
it cannot be reached 
for adjustment. Fig. 131 
shows this clearly. This 
form causes trouble in 
assembling because the 
male cone A must be put 
in place with the spring 

Fig. 131. Typical Reversed Cone Clutch . 

between it and the fly¬ 
wheel C, before the female B can be set into its place and bolted 
up. These two big sources of trouble have caused designers to turn 
to the direct type more freely, as it lends itself readily to an external 
adjustment. If the spring is outside, it is easily put into place and 
as easily taken out. Fig. 132, which illustrates this, is a section 
through the Bayard (French) clutch, and the spring is seen to be 
entirely outside the clutch proper. Its location is such as to permit 
the adjustment of the tension at any time, by means of a screw collar 
C, which may be done with no more trouble than lifting up the 
footboard of the car and turning the collar forward a few turns. 

Not all designers have hit upon as happy a solution of the clutch 
problem as this. Thus, in the Studebaker clutch, shown in Fig. 
133, the spring B is external to the clutch but so placed that it is 























GASOLINE AUTOMOBILES 


175 



necessary to disconnect the universal joint A A, take it off the car, 
loosen a set screw, adjust, and then repeat the other operations in 
reverse order. A similar state of affairs is found in the Benz, illus¬ 
trated in Fig. 134, in which it is necessary to take out the bolts 
connecting the shifting collar to the male member, and then, through 
the longitudinal motion permitted by the 
form of universal joint used, slide this back¬ 
ward as far as possible. The latter move¬ 
ment allows of removing it from place, then 
the spring tension may be adjusted by sim- 


Fig. 132. Bayard (French) 
Direct Cone Clutch 


ply removing a cotter pin and the nut it holds. 

Fig. 135 gives a better idea of a male 
clutch member than does a line drawing. 
This shows how the leather lining usually 
used is fastened to the metal ring or spider 
by means of rivets. In the up-to-date car 
this method will be found to have been 
carried even farther than this, the leather 
being put on in sections, so that in case of unequal wear a single, 
worn-out section may be replaced without disturbing the others. 
An even later idea emanates from England, and is nothing less than 
putting these sections onto the cone by means of dovetails. In this 
way a worn section can be replaced in the length of time that it 
takes to tell about it. 

Double and Triple Cones . A prominent German maker has been 
very partial to the double-cone form of clutch, particularly for large 
and high-powered cars. This has generally consisted of a pair of 
single direct clutches set back to back, and coupled up in such a way 











































Fig. 133. Studebaker Direct Cone Clutch 
Courtesy of Studebaker Automobile Company, South Bend, Indiana 



Fig. 134. Benz (German) Cone Clutch with Somewhat Inaccessible Clutch Spring 


338 























































































































































































































































GASOLINE AUTOMOBILES 177 

that pressure on the pedal acted upon the two progressively; that is, 
they were engaged one after the other. Conversely, the initial 
declutching pressure worked gradually upon one until that was 
entirely out of engagement, when 
a continued pressure would grad¬ 
ually throw T out the other. For 
very large motors, this has a dis¬ 
tinct advantage in that the speed 
can be temporarily reduced by 
applying the clutch pedal part 
way. In this case one of the two 
clutches is thrown out, and the 
one left, not being able to carry 
all the motor power, slips and 
thereby reduces the speed. A 
quick pick-up and very rapid 
acceleration can then be had, 
when the need for reduced speed 
is removed, by simply dropping 10 _ „ , „ . ^ . 

in the second clutch. Narrow Leather to Carry Load 

Somewhat the same idea is presented in the triple cone clutch 
shown in Fig. 136. This has three different sizes of cones, each one 
meshing, or contacting, with a smaller section of the cone housing. 
All three are on the same splined shaft, and the arrangement is such 
that each part has its own 
spring, and thus is self-con¬ 
tained. When the clutch col¬ 
lar is pushed to the left, the 
smaller cone is disengaged. 

A further movement of about 
^ inch and its hub comes in 
contact with the hub of the 
middle-sized cone, a contin¬ 
ued movement disengaging it. 

Similarly with the third cone. 

The reverse action takes place on engagement, the larger part 
clutching first, then the intermediate, and lastly the small cone. 
In this way, a smooth and gradual action is obtained. The facing 



Fig. 136. New Type of Triple Cone Clutch 



339 



















178 


GASOLINE AUTOMOBILES 


is plain metal, which contacts with metal on a 4-degree taper. It runs 
in oil. The over-all length is but 11J inches for a 35-horsepower unit. 

Requirements Applying to All Clutches. In a serviceable clutch 
there are two general requirements which are applicable to all forms. 
These are gradual engagement and large contact surfaces , although 
the latter requirement may be made to lose much of its force by 
making the surfaces very efficient. In the cone clutch, gradual 
engaging qualities are secured by placing a series of flat springs under 
the leather or clutch lining. By means of these springs, acting against 
the main clutch spring, the clutch does not grab, since the large 
spring must have time in which to overcome the numerous small 
springs. In this way the engagement is gradual and the progress of 
the car is easy as well as continuous. 

The specific necessity in a cone clutch, whether it be direct or 
inverted, is a two-fold one— sufficient friction surface, and proper 
angularity. As the latter, in a way, effects the former, as will be 
discussed more in detail later, this really reduces to one complex 
requirement. 

The angularity varies in practice from 8 to 18 degrees. In 
arriving at these figures, a line of reasoning is followed somewhat like 
the following: 

The force of the spring acts along one leg of a right triangle of which 
the resulting useful force is found to lie along the hypothenuse, the latter 
being perpendicular to the surface of the clutch. In this case, the ratio of 
the resulting useful force x to the original spring pressure A is the ratio of 
1 to the sine of the angle of the clutch cone 6 • Expressed in the form of 
proportion, it is 

x:A : : 1 : sin 6 

or as an equation 

x _ 1 

A sin 0 

Since 1 is a constant, reducing sin 0 increases the ratio. Reducing 
the sine, in turn, means reducing the angle itself, and this is the 
course usually pursued as a large ratio is desired. For this reason 
small clutch-cone angles are used. The actual angle is, however, 
partly determined from another basis. 

Coefficient of friction is the name given to the adhesion of two 
materials one to the other, under just such conditions as are described 
above. Since it is impossible to have perfect adhesion/this coefficient 





GASOLINE AUTOMOBILES 


179 


is always less than unity. Now, the angle of the cone of a cone-type 
clutch is dependent solely upon the coefficient of friction of the 
materials selected and the condition of the friction surfaces. Quite 
frequently, in fact, usually, the materials of cone clutches are leather 
and cast iron; i.e., the female cone is either a part of a cast-iron 
flywheel or made of cast iron, while the male cone is usually some 
other material lined with leather. The ordinary male cone is of very 
light metal, so as to reduce the spinning action of this rapidly rotated 
mass. Of late years, aluminum has met with favor for this part. 

The coefficient of friction for cast iron and leather has been 
determined as .30 dry, and .25 greased. Since the latter case is more 
usual this value will be used. Expressed mathematically, the coeffi¬ 
cient of friction is the tangent of the angle of repose, so for this value 
it would be the angle of which .25 is the tangent. This is 14 degrees. 
A more conservative value of the coefficient is .20, for which the angle 
is but 11 degrees. 

In the design of the clutch, however, a more accurate method 
than this is pursued. The twisting moment in foot-pounds M is equal 
to the horsepower P, reduced to foot-pounds, divided by the speed at 
which the power is to be transmitted. This gives the equation 


M = 


P 33,000 


, or roughly, 


P:5250 


2 t rP — R 
Let S represent the torsional resistance, to which the clutch 
must at least be equal, and F the mean or average radius of the male 
cone in inches 


then 


P 63,000 
FR 


If, now, the resulting pressure from the clutch spring acting 
normal to the clutch surface is z, the axial pressure or total exerted 
by the spring is x, and the coefficient of friction is/, then 

2 = and S = zf=^P- 
sin 6 sin 6 

Equating the two values for S, and solving for x 

P 63,000 sin d 


x, spring pressure = 
and solving for P 


FRf 


P, power transmitted = — a 

* 63,000 sin 0 







180 


GASOLINE AUTOMOBILES 


Contracting=Band Clutch. A short consideration of the band 
style of clutch shows that this does not differ radically from the ordi¬ 
nary band brake, either in con¬ 
struction, application, or actual 
working. The difference in the 
two lies in the fact that the 
band, as a clutch, is designed 
to transmit power with as little 
loss as possible, while the band 
as a brake is designed to 
absorb the forward energy of 
a moving vehicle (equal in 
the last analysis to power) in 
the shortest possible space of 
time, i.e., to waste as much 
power as possible. 

Fig. 137 shows the form of 
band clutch used on the Mors 
(French) cars. In this form, the 
band is in two parts, and a rocker arm moved by a sliding cone 
operates the free ends of the two bands, which thus contract upon 



the clutch drum. Fig. 138 is the clutch which was used on Gaeth 
cars, made in Cleveland, Ohio. While not differing radically 



Fig. 137. Mors (French) Contracting- 
Band Clutch 



























































GASOLINE AUTOMOBILES 


181 


from the Mors, this has the two parts or sections of the band united 
at the bottom and two operating levers are pivoted at the top, where 
a single conical-shaped cam moves both outward and tightens the 
bands on the drum. 

The usual place in which the band clutch is found is in connec¬ 
tion with a planetary transmission. There the band is always used, 
and there it reaches its simplest form, that of the plain band wrapped 
around the drum. One end is fixed and the other attached to the 
braking, or more correctly the clutching lever. A plain pull on this 
effects the clutching action. A more modern and more efficient form 
has one end of the band attached to one extremity of the clutching 
lever, while the other end of the band is fastened to the middle of 
this lever. The clutching pull comes upon the upper extremity of 
the lever. Then the band acts to aid in clutching itself, i.e., a 
scissors action is obtained, and the required pull is lessened. 

This can be seen quite plainly in Fig. 168 on page 215, which 
shows the planetary transmission and bands used on Ford cars. In 
this, the low and reverse speed bands are shown in full. This is 
of particular interest as Ford is now the only American maker using 
the planetary form of transmission, all other makers, even of very 
low-priced machines—some below the Ford price—having gone to 
the selective sliding gear form. 

When the band is used as a brake the pull necessary to stop the 
car is 


, D 
P=f w -J 


in which / is the coefficient of friction, w the weight to be stopped, 
D the diameter of the road wheels, and d the diameter of the brake 
drum. Now the ratio of the diameter of the road wheels to that 
of the drum is but the ratio of the work arm to the power arm, so 
when the band is used as a clutch, the ratio of the radius of the two 
arms may be substituted. The power arm is taken as unity and the 
work arm as the radius of the clutch drum. Since this divided by 
1 remains the same, it may be substituted in the formula above. So, 
too, with the weight, in place of this must be substituted the power 
to be transmitted, which is the equivalent of the weight in the other 
case. The formula then becomes 

v'=fPr 


182 


GASOLINE AUTOMOBILES 


Owing to the winding action of the band, the pull p' will be less 
than the pull p, by an amount which varies as the portion of a circle 
or number of degrees encircled by it. Then taking 6 as the number of 
degrees) 


log V 
log p' 


= .434/0 


from which the value of p r may be evaluated in terms of p and sub¬ 
stituted in the previous formula. 

Expanding=Band, or Ring, Clutch. The expand;ng-band clutch 
finds favor among few. Like the contracting band, which is very 
similar to the band form of brake, the expanding band is much like 
the expanding type of brake, with the exception that the clutch is 
used to form the connection between two rotating parts. Viewed 
from the standpoint of pure engineering, the expanding band is 
little different from the cone type of clutch, granting that the angu¬ 
larity of the operating cam is the same as that of the cone. 

Much depends upon how the band is expanded, the methods 
differing widely in practice. This is usually accomplished by means 
of screws, which may be either right-handed, or left-handed, or both. 
In one expanding clutch, the screws are single and right-handed. 
This superinduces a gain in the power required to clutch by the 
amount of 


. . . 2irl 

A, gam in power =- 

s 


in which l is the length of the lever in inches, and s the pitch of the 
screw in inches. If the screw is made double, i.e., one-half threaded 
right-hand and the other half threaded left-hand, then the expression 
should be halved. This latter case being more usual, it will be of 
interest to resolve the gain into the original formula for power, i.e., 

p_ fFRxl 
63,000s 

Another form is expanded by a double-threaded screw operated 
by a lever. This, in turn, is moved by a pair of sliding collars on 
the main clutch shaft, the clutch foot pedal moving these forward. 

Disk Clutch. With its advent in 1904, the multiple-disk clutch 
has steadily grown in popularity until today it is looked upon as the 


344 





GASOLINE AUTOMOBILES 


183 


most satisfactory solution of the difficult clutch problem. Designers 
who have once adopted it, seldom, if ever, go back to another form, 
while of the new cars coming out from time to time nearly three- 
fourths are equipped with some form of disk clutch. 

Popularity Compared with Other Forms. Statistics for 1914 show 
that the disk form of clutch was easily the most popular type, and 
further comparisons with the previous year, and with the apparent 
tendencies for 1915, show that it is gaining more rapidly than any 
other type. Of 230 different chassis for 1914, 119 were equipped with 



disk clutches, 97 with the cone, 9 with a contracting-band type, and 
but 5 with an expanding-band form. As the majority of the newer 
models have adopted this form also, while several of the others have 
changed, the relative figures for 1916 are estimated at about 94 
disk, 81 cone, no contracting band, no expanding band, and 1 electric. 
This would give the first-named approximately 54 per cent of the total. 

Two Forms of Same Make. This brings to mind the relative 
advantages of the two leaders, the cone and the disk. This is pre¬ 
sented in a very striking manner in Figs. 139 and 140, which show 
the cone and disk clutches used interchangeably by the Austin Motor 


345 



















































184 


GASOLINE AUTOMOBILES 


Company, Birmingham, England, in the 18-24-horsepower chassis. 
Note in these two that the cone requires a considerably greater 
length, for in that form it is necessary to make the flywheel with a 
sloping series of spokes in order to throw the cone farther forward, 
and thus make room for the greater length of spring. Note that the 
larger diameter of the cone and its inevitable flywheel action has 
resulted in the removal of considerable metal from the inside rim of 
the flywheel. Furthermore, on the disk form, note how the space 
between the compact disks and the rim of the flywheel is used as a 



Fig. 140. Disk Clutch for the 18-24 Austin for Comparison with Fig. 139. 


fan, six blades being set in here in place of spokes, these assisting in 
cooling the water. 

While the cone is apparently more simple, it will be noted on 
closer inspection that the pedal and other operating mechanisms are 
all shown in the disk form,- while none are shown in the cone type. 
If the two drawings were on a par, they would show little or no dif¬ 
ference in this respect beyond the fact that the disks and their springs 
make some 40 or 50 parts, while the cone and its spring parts do not 
total much more than half a dozen. 

On this cone form, special attention is directed to the method of 
applying the clutch lining in six sections, with a single bolt and clip 
above each. It is said that any one of these lining sections can be 






















































GASOLINE AUTOMOBILES 


185 


removed in a couple of minutes without touching any other parts. 
In both instances, note the braking surface provided to stop spinning 
when the clutch is removed. In the case of the cone, this is a single 
conical surface at the left of the figure, while on the disk it consists 
of a pair of wedge-shaped projections which enter a pair of similarly 
shaped grooves, this giving actually four braking surfaces. In the 
latter, too, attention is called to the simple adjusting means, a single 
large set screw, with a locknut, being so placed that when the throw 
of the pedal is not just right for 
engaging or disengaging, a turn 
of the screw allows of more or 
less movement, according to the 
needs. 

Simple Type. These differ 
in number and shape of disks, 
method of clutching, material, 
and lubrication; but in principle 
all are alike. This, briefly stated, 
is that flat surfaces properly 
pressed together will transmit more 
power with less [trouble than any 
other form. By multiplying the 
number of surfaces and making 
them infinitely thin, the power 
transmitted may be increased in¬ 
definitely. That this is not idle 
fancy is shown by a number of 
very successful installations of 
1000 horsepower and over in marine service, and certainly no such 
power is required for an automobile. 

The minimum number of plates in use is said to be three, but 
very often the construction of a three-plate clutch is such that one or 
two surfaces of other parts are utilized, making it a two- or even one- 
plate clutch in reality. Thus, in the Austin clutch, shown in Fig. 141, 
made by the Austin Automobile Company, Grand Rapids, Michigan, 
a copper disk G of some thickness is clamped by spring pressure 
between the flywheel A and a floating ring D. In reality, the copper 
disk transmits all the power, the flywheel being a necessity, and the 



Fig. 141. Austin Clutch with Single Disk 
Austin Automobile Company,*Grand 
Rapids, Michigan 




347 



























186 


GASOLINE AUTOMOBILES 


floating disk only an accessory before the fact. It would, therefore, 
not be wrong to call this a one-plate clutch. 

Multiple-Disk Clutches. The modern tendency in disk clutches, 
however, is away from those of few plates requiring a very high 
spring pressure—since the friction area is necessarily limited— 
toward the multiple-disk variety, in which a very large area is 
obtained. This allows of a very light spring pressure, and conse¬ 
quently is easier to engage and disengage and, for this reason, it is 
becoming more popular with owners and drivers than the variety 
requiring the extra-heavy effort. The construction of the three- 
plate disk clutch does not differ radically from one maker to another. 
Three fingers are used to clutch and declutch generally, the amount 
of movement being adjustable. A single spring of large diameter 



Fig. 142. Lanchester (English) Disk Clutch and Disk Brake 


and large-sized wire is generally used, and sheet steel is used for 
one-half the clutch plates. Between the three-plate and multiple- 
disk are many gradations. 

In the true multiple-plate clutch, there are three general varieties 
met with in practice: the metal-to-metal with straight faces; the 
metal-to-metal with angular or other shaped faces, designed to 
increase the holding power; and the straight-face kind in which metal 
does not contact with metal, one member being either lined with a 
removable lining or else fitted with cork inserts. 

Disk Clutch and Disk Brake. A most unusual combination 
of clutch and brake is to be found in the English Lanchester cars. 
In this, as shown in Fig. 142, the multiple-disk clutch is placed at 
the forward end of the shaft, and consists of 12 external or driven 


348 
























































GASOLINE AUTOMOBILES 187 

disks and 11 internal or driving disks. These are comparatively 
small in size, and are stamped from flat pieces of steel, the external 
members having a square shape, with a projecting key at each corner, 
while the round internal members have six projecting keys. 

The latter fit onto a splined shaft on which the keys correspond 
with the spaces inside the driving disks, while the keyways cor¬ 
respond with the projections or keys in the disks. In this way, all 
the driving disks are driven by the 


is an external or driven disk. These 
have their keys fitted into four slots 
in the corners of a square hole in a 
driven sleeve or casing. 


When the two are pressed to¬ 
gether by means of the pins shown, 
the oil in which the disks run nor¬ 
mally is gradually squeezed from 
between them, and the driving 
disks slowly take hold on each side 
of each driven disk, so that all of the 
latter are carried around with them. 

These must take the casing with 

them, because they are keyed into it, consequently when the oil is en¬ 
tirely squeezed out and the disks grip, the whole clutch revolves as a unit. 

The brake, which is shown directly back of the clutch, but which 
is operated by a separate pedal, is constructed in exactly the same 
manner and is similarly operated. There is this exception, however, in 
that the external rings—the driven members in the case of the clutch— 
are in this case entirely stationary, being held by keys on the casing, 




















































188 


GASOLINE AUTOMOBILES 


which cannot turn. That being the case, as the pressure is applied 
through the medium of the foot pedal, and as the oil is squeezed from 
between the nine external and eight internal plates, the power is 
gradually absorbed, and the car slows down or stops according to 
the amount of force applied and other conditions. The two sets 
of plates are identical, and except for their number, are inter¬ 
changeable. As has been stated, all these run in oil, and to make 
sure of a copious and continuous circulation, an oil pump is placed 
in the bottom of the rear end of the casing, being driven off the main 
shaft. To facilitate its use, the bottom of the case forms an oil well. 



Fig. 144. Multiple-Disk Clutch and Transmission of Winton Cars 
Courtesy of Winton Motor Car Company, Cleveland, Ohio 


Metal-to-Metal, Dry-Disk Type. This method has the additional 
advantage that the central part within which the clutch is housed 
is very small in diameter, so that the portion of the flywheel between 
the rim and the clutch housing may be made in the form of fan spokes, 
thus converting it into a fan and serving to cool the motor better. 

Many designs follow this method, one [prominent example being 
shown in Fig. 143. This is of the all-metal type with plane faces, 
used by the French constructors, Panhard and Levassor. 

In this type, the spring presses the member P forward, jam¬ 
ming one-half the disks against the other half, this jamming action 
transmitting the power. To throw out the clutch, the lever L moves 





































GASOLINE AUTOMOBILES 


189 


backward and pulls with it the casing M, this being connected to the 
member P draws the latter out and away from the disks. The natural 
spring of the latter then asserts itself, and they free themselves. 

As the various examples of disk clutch shown would indicate, 
the designer has had his choice between a few large disks and a large 
number of small ones. If he chose the former, the clutch could be 
housed within the flywheel, 
but this makes it inaccessible, 
although saving length. If he 
chose the latter, the clutch 
could not be kept within the 
flywheel length, a separate 
clutch housing being a neces¬ 
sity, but the clutch could be 
made accessible and flywheel 
fan blades could be used. 

Another example of the 
plain metal-to-met al disk 
clutch is shown in Fig. 144. 

In this case also the clutch is 
not housed in the flywheel, as 
in most of the preceding exam¬ 
ples of this form of clutch, but 
in the forward end of the 
transmission case. That is, 
instead of motor and clutch 
forming a unit, the latter is a 
unit with the transmission. It is claimed that this position makes it 
more accessible, since it brings the clutch directly under the floor 
boards of the driver’s compartment, and that better lubrication is 
another result. The latter is effected through communication with 
the gear part of the case, which is always filled with lubricant. 

In the figure it will be noted that there are 13 driven disks, with 
keyways, which hold them to the driven drum. Note that the latter 
is held to its shaft by means of a pair of large set screws. The clutch¬ 
ing springs are of small diameter and size, spaced equally around the 
periphery of the disks, each being enclosed in a small and thin metal 
casing. Attention is called also to the universal joint shown, this 



Fig. 145. Argyll (Scotch) Disk Clutch 






































190 


GASOLINE AUTOMOBILES 


forming the rear end of the driving connection with the flywheel, 
which will be referred to later. These disks are perfectly flat, stamped 
out of sheet steel with the proper keyways for internal or external 
holdings. 

Differing from the foregoing is the clutch used on the Scotch 
Argyll cars, Fig. 145. In this the disks have been made larger in 
diameter and smaller in number. Moreover, no use of the flywheel 
as a fan has been attempted. 

Use of Facings. The more modern disk clutch has two sets 
of sheet metal disks, one of these being faced on one side or both 
with a special material. Without a single exception, all the disk 

clutches shown have had 
plain disks against plain 
disks. This makes a sim¬ 
ple and fairly inexpensive 
construction, but as has 
been found out recently, 
one that is not very effi¬ 
cient. Thus, the most 
recent tests have shown 
that metal against metal 
gives a coefficient of fric¬ 
tion of but .15, which is 
reduced to .07 when the 
surfaces become oily or 
greasy. With one of these 
contacting faces lined with leather, this rises to .23 when dry, and .15 
when oiled. Again if fiber is used for the % facing, the coefficient 
becomes, respectively, .27 and .10, while with cork or cork and leather, 
it becomes, respectively, .35 and .32. Here then is a very apparent 
reason for (1) facing the clutch disks, and (2) running them dry. 

By going over these figures, it will be noted that disks with 
almost any form of facing will show an increase in efficiency over the 
same disks without facing, varying from 60 up to almost 300 per 
cent. Again, any form of disk clutch, faced or otherwise, will show 
a much higher coefficient dry than oiled, and thus, a greater effi¬ 
ciency. These two facts point out the obvious reasons for the modern 
tendency toward the multiple-disk clutch, faced and running dry. 



Fig. 146. Multiple-Disk Clutch Used on Cadillac Cars 
Courtesy of Cadillac Motor Car Company, 

Detroit, Michigan 



GASOLINE AUTOMOBILES 


191 



To present an example of the faced type, Fig. 146 shows the 
multiple-disk clutch of the eight-cylinder V-type Cadillac. In this, 
the eight driving disks can be seen, with the facing on each side of 
each one. This facing is of wire-mesh asbestos, and between each 
pair of disks comes a plain driven disk, so that it has a facing of the 
asbestos against each side of the metal which it grips. The six keys 
which hold and drive the outer disks can be seen on the inside of its 
housing, while the slots into which these project can be seen on the 
periphery of the disks. By examining the group closely, the driven 
plain disks can be seen between each pair of the drivers. Fig. 147 
shows the pedals and the exterior of the clutch case, where it bolts 
up to the engine. This 
indicates how a unit power 
plant simplifies the control 
group, and eliminates parts. 

Floating Disks , a Nov¬ 
elty. The clutch on the 
Locomobile cars, shown in 
section in Fig. 148, is very 
much like the Cadillac just 
shown, except for this novel 
feature, that the fabric 
facings are not attached 
either to the driving or to 
the driven disks, but float 

between them. This fabric, Fig. 147. Housing and Foot Pedals on the 

usually a woven asbestos 

material with a central core of interwoven metal wires, instead of 
being attached to both sides of every other disk or to one side of 
every disk, is not attached at all. The rings for the fabric disks are 
made up in the form of annular rings, have the same inner diam¬ 
eter as the inside of the driving disks, and the same outside size 
as the driven disks; consequently assembling one of these clutches 
is simply a question of piling first a driven disk, then a fabric, 
then a driving disk, and so on. 

Because of the fact that the fabric rings are not united to either 
of the metal disks, they free themselves with remarkable rapidity so 
that either on engagement or on declutching the action is very quick. 


192 


GASOLINE AUTOMOBILES 



Fig. 148. Floating Dry Disk Clutch Used on Locomobile Cars 



354 




















































































































































GASOLINE AUTOMOBILES 


193 



Greater Power Transmitted by Surfaces Not Plane. To increase 
the power transmitted by a clutch of given size, either the number of 
plates must be increased or the form of the surface changed. The 
latter method was followed on the clutch of the French car, Ours. 
The disks of this unusual clutch had a perfectly flat outer portion, 
and a conical inner portion, only the latter taking part in the trans¬ 
mission of power. In this disk form, then, we have the advantage 
of the disk economy of space, together with the advantages of 
the cone clutch, and the additive gain of running in a bath of oil. 


Fig. 150 Fig. 151 

Disassembled Hele-Shaw Clutch 

Another form utilizing this principle, and one that is more widely 
used, is that known as the Hele-Shaw, so named from its inventor, 
the famous English scientist, Dr. H. S. Hele-Shaw. This is essen¬ 
tially a flat disk, as shown at A, Fig. 149, with a ridge B at about 
the middle of the friction surface, this ridge consisting of a portion 
of the surface, which has been obtruded during the stamping process 
in such a way as to leave the surface of the ridge in the form of an 
angle of small size. The angle used is 35 degrees, and this value has 
been determined upon experimentally as the best. Fig. 149 shows a 


355 


194 


GASOLINE AUTOMOBILES 


cross section through an assembled clutch, which reveals the clutch 
angle very plainly. In use, the ridges nest one on top of the other; 
and in the extreme act of clutching, not only the flat surfaces but 
both sides of the ridge are in contact with the next plate. Thus, not 
only is the surface for a given diameter increased, but the wedge 
shape is also taken advantage of. Smaller views of the single disks 
and of the complete clutch, disassembled to make plain its simplicity, 
are shown in Fig. 150 and Fig. 151. 

A brief mention of the method pursued in the design of flat disk 
clutches will not be out of place. Consider the disk to be used as an 
annular ring having an internal radius r h and external radius r 2 . 
If / is the coefficient of friction, n the number of disks, and p the 
specific pressure normal to the friction surfaces as distinguished from 
the spring pressure, then by certain theoretical considerations involv¬ 
ing integral calculus, it is found that the moment M of the clutch 
around the center will be as follows: 


M, total = Pfj&LZ}} 
18 


(r 2 3 —n 3 ) in foot-pounds 


In use, the factor p is found first, by figuring the area of the whole 
surface and dividing the spring pressure by it 


thus area = t (r 2 2 — ri 2 ) 

and the specific pressure is 

_ spring pressure 
^ (r 2 2 — ri 2 ) 

Knowing the material, the coefficient of friction is known, and there¬ 
fore everything is known but the number of plates and their size. 
By trial the size may be selected, from which the number is easily 
figured, using the above formulas. Care should be taken in their 
use to add 1 when the number of plates comes out with a decimal or 
fractional quantity. In the use of a formula like the preceding 
one, it is always assumed that the power is known at some specific 
speed. This being the case, the total torque, which is ditided by 
the total moment to find the number of the plates to use, is 


T, total = 


frpX33,000 


2 7r X speed 

Hydraulic Clutches. All the methods of engaging and dis¬ 
engaging the engine at will, as discussed before, have been of a 





GASOLINE AUTOMOBILES 


195 


mechanical nature. The hydraulic clutch, on the other hand, par¬ 
takes more of the fluid nature, although semi-mechanical, i.e., 
operated by mechanical means. Ordinarily it is in the nature of a 
pump with a by-pass, the pump working at ordinary speeds to force 
the heavy liquid, usually glycerine, through the by-pass. To clutch 
up tightly, however, the by-pass is closed and, the liquid being unable 
to circulate while the pump continues to operate, the whole device 
is rotated as a unit. In this case it operates just as any other clutch, 
but, due to the sluggish action of the fluid, it is slower to respond. 
Then, too, there is always present the grave question of leakage, 
since the smallest leak puts the clutch entirely out of use. These 
disadvantages, together with the necessary complications, have 
retarded the development of the hydraulic form so that there are 
few of them in use today. In the clutch shown in Fig. 152, a spider 



Fig. 152. Stilson Hydraulic Clutch 


is fast to the engine shaft and carries two spur gears B B. These are 
constantly in mesh with C, which is fast to the driven shaft. The 
space surrounding these gears is filled with oil, which is pumped 
around by the rotation of the gears. Several valves, one of which is 
shown at D, allow the oil to circulate freely. Under these circum¬ 
stances, the pinions on the crankshaft run around the gear on the 
driven shaft and transmit no motion to the latter. These valves are 
held open by springs, but by the operation of the foot pedal, a cone 
is brought forward which presses against the heads of the valves, 
closing them. Partly closed, the pinions drive the gear slowly, 
because of the resistance which the liquid offers, and when wholly 
closed, the transmission shaft is driven at full speed with little 
loss, since the fluid is not very compressible. This clutch was for¬ 
merly made by the Stilson Motor Car Company, Pittsfield, Massa¬ 
chusetts, which firm has since gone out of business. 


357 













196 


GASOLINE AUTOMOBILES 


Another clutch designed with the same idea, but worked out 
in a far different manner, is that of the North Chicago Machine 
Company, North Chicago, Illinois, and shown in Fig. 153. This 
clutch is more complicated and has many more parts than the 
Stilson clutch, but has the advantage of having seen more severe 
trials and more actual service. It acts as does the Stilson, oil nor¬ 
mally passing through passages when the clutch is out, but when 
prevented from passing, the whole mechanism turns as a unit. The 
prevention of the liquid passing is accomplished by an eccentric 
device not very different from a vane type of water pump, the 
method of throwing it into and out of engagement being very com¬ 
plicated. Fig. 153 shows all the parts, and a study of it will reveal 
the complete action. 




Fig. 153. Pambla Hydraulic Clutch 
Courtesy of North Chicago Machine Works, North Chicago 

Magnetic Clutch. All the foregoing clutches present in one 
form or another very complicated devices for freeing the transmission 
shaft from the engine shaft, but the magnetic clutch is a device which 
has simplicity for its foremost argument. The magnetic clutch, 
consists primarily of three parts: the field, usually in the form of a 
ring; the armature always of ring shape; and the oil casing shaped 
to accommodate the other parts, its function being that of a cover, 
simply. The armature is a simple cast-iron plate of rectangular 
section, adapted to be drawn into engagement with the field, when 
the latter is energized. 

The field, on the other hand, is made up of the back plate, 
the inner and outer field rings, the magnetizing coil and the contact 
rings. In operation, the accelerator is energized by closing the 
electrical circuit, which sends a current through the field. This 
magnetism attracts the armature, which then moves laterally, clos- 


358 





















GASOLINE AUTOMOBILES 


197 


ing the very small gap between the two. The oil in which the 
whole clutch works prevents it from taking hold suddenly, or grip¬ 
ping, but as this oil film on the two surfaces is gradually squeezed 
out, the clutch as gradually takes hold. 

New Electric Generating Clutch. So great has been the interest 
in the various electrical mechanisms in the automobile, and so 
quickly has the public taken up with all these that this has stimu¬ 
lated an entirely new invention, called, by its maker, the Vesta 
Accumulator Company, Chicago, a centrifugal electric-generating 
clutch. This name gives a little clue to its action, which is a com¬ 
bination of the usual friction clutch and that of the electric-magnetic 
drag between armature and fields of any electric machine. 

In addition to its clutching feature, its ability to drive when 
partially clutched makes it, in effect, a transmission, so that it is 
designed to replace the usual clutch, gearset, flywheel, electric gen¬ 
erator and starting motor. It is composed of two parts: an arma¬ 
ture, which becomes the flywheel; and a field mounted on the pro¬ 
peller shaft. The former carries an internal commutator, and the 
latter, brush holders which hold brushes against the commutator. 
These are mounted so that the centrifugal force of rotation increases 
the force with which they press against the commutator. Thus 
there is a variation from practically no contact up to the maximum, 
at which point the centrifugal force is so great that field and arma¬ 
ture revolve as a solid unit. 

An automobile built in France — the Ampere — uses this con¬ 
struction exclusively, the master clutch being dispensed with in 
favor of an individual clutch transmission, the clutches being mag¬ 
netically operated as just described. In addition, the differential is 
dispensed with, and in its place is used a pair of magnetic clutches, 
one for each wheel. The differential action is obtained on curves 
by decreasing the current to the clutch on the inner wheel up to a 
certain point, at which it is cut off entirely. This gradual reduction 
and cutting off of the current is accomplished automatically by the 
movement of the steering wheel. 

Clutch Operation. Practically all modern clutches are operated 
by means of a special pedal, moved by the left foot. This is con¬ 
nected by means of rods and levers to the internal member, which 
compresses the clutch spring or springs, thus allowing the clutch 


359 


198 


GASOLINE AUTOMOBILES 


members to separate. In this way the clutch is thrown out. To 
throw it back in, the foot pressure is removed from the pedal, the 
springs again exerting pressure and forcing the parts together, thus 
allowing them to take hold. There was a time when a considerable 
number of cars had the clutch so constructed that the pedal held it 
in and the springs threw it out, just the reverse of the present plan. 
This, however, is no longer used, as it necessitated maintaining a 
constant pressure on the pedal while driving, and after a long 

ride this became very 
fatiguing. 

Gradual Clutch Re= 
lease. The Dorris clutch 
made by the Dorris 
Motor Car Company, St. 
Louis, Missouri, Fig. 154, 
is a new arrangement of 
the clutch pedal, and its 
operation is such that 
the clutch is released or 
thrown out with very 
light pressure on the 
pedal. Pressure on the 
pedal A is transmitted 
by the shorter lever arm 
B, thus greatly increas¬ 
ing the leverage. This 
pressure is transmitted 
to lever C and through 
it to lever D, these two 
As C is much longer than 
This does not act directly 
upon the clutch, but upon the upper end of the clutch shifter F, which 
is attached to the clutch at G and pivoted at its lower end H —here 
again in a multiplying action. The net result of these three multi¬ 
plications is a combination which will release the strongest and 
stiffest clutch with a very slight pressure of the foot. 

Clutch Lubrication. As has been previously pointed out, some 
clutches run in oil, while others run dry. The former type must be 



Fig. 154. Multiplying Lever of Dorris Clutch to 
Make Pedal Pressure Light 

Courtesy of Dorris Motor Car Company, St. Louis, Missouri 

being hung on the frame across member E. 
D, there is another multiplying action here. 


360 































GASOLINE AUTOMOBILES 


199 


kept filled with lubricant at all times, the general plan in such a case 
being to provide a lead from the engine oiler when the clutch case is 
separated from the engine case, or a connecting means when the two 
are in one case. In addition to the actual clutching members, there 
is practically always a sliding member, which must have lubricant of 
some form, while the thrust bearings to take the thrust of the clutch 
springs must be cared for. Generally, these two cases are cared for 
by a pair of grease cups, these being visible in Figs. 133 and 139. 
The operating rods are lubricated usually by means of small oil holes, 
either drilled directly into the part or covered with a small oil cup. 
In those cases in which the clutch runs in oil, it will be noted that a 
filling plug is provided, by means of which additional lubricant can 
be poured into the casing. For this, refer to Figs. 136, 140, 145, 
and 149. 

Clutch Bearings. The need for bearings in a clutch depends 
somewhat upon its nature and location, but regardless of these a 
thrust bearing is needed for the clutch spring. To explain this 
briefly, it is known that action and reaction are equal, and opposite 
in direction. For this reason, when a clutch spring presses the disks 
or parts together with a force of, say, 100 pounds, there is exerted 
in the opposite direction this same force of 100 pounds. In order to 
have something for this to work against, a bearing is used, and since 
it takes up this spring thrust, it is called a thrust bearing. Not all 
bearings are fitted to take thrust, the majority of them being designed 
for radial loads only. For this reason a special design is needed. 

When the clutch is incorporated in the flywheel, there are 
needed, generally, two additional bearings, one for the end of the 
crankshaft and another for the transmission or driven shaft. This 
will be noted in Figs. 131, 140, 141, 148, 149, and 144, although the 
last-named does not have the clutch combined with the engine, but 
rather with the transmission. In the majority of cases, it will be 
found that a means of fastening the end of one shaft has been worked 
out so as to eliminate one bearing. This accounts for the large 
number which show but two—the thrust and one other. In looking 
back over these, it will be noticed also that practically all the bearings 
are of the plain ball form. This is due in large part to the fact that 
these take up the least room for the load carried, both in diameter 
and width, a contributing reason being the fact that in many cases 


361 


200 


GASOLINE AUTOMOBILES 


one of the shafts or parts can be formed to take the place of either 
the inner or outer ball race. 

Clutch Adjustment. In general, adjusting a clutch is not a 
difficult task, there being but two possible sources of adjustment ; the 
throw or movement of the operating pedal or lever, and the tension 
of the spring. Generally, an adjustment is provided for each. When 
the fullest possible throw of the pedal does not disengage the clutch, 
an adjustment is required to give a greater throw. If the throw is 
correct, but the clutch takes hold too quickly and vigorously, then the 
spring pressure can be lessened somewhat to soften down this action. 
On the other hand, when dropped-in quickly, if it takes hold slowly, 
more spring pressure is needed, which is obtained by tightening. 

Clutch Accessibility. Clutches are made accessible in two ways: 
by their location on the car, and by the relative ease with which they 
can be removed. Accessibility as to location is less in the various 
combinations, such as in the unit power plant, housed within the 
flywheel, or combined with the transmission. Ease of removal is 
determined by the number and location of the joints (usually uni¬ 
versal) used with the clutch. Sometimes, one on each side makes 
removal easy, but generally, a single universal makes much work. 

CLUTCH TROUBLES AND REMEDIES 

The very fact that the clutch is a more or less flexible—or rather, 
variable—connection between engine and road wheels makes it 
necessary that it be kept in the best of shape. It is rather surprising 
to the novice, with his first clutch trouble, to have his motor racing 
at the highest possible speed, and to find his car barely moving, but 
to the experienced driver it is humiliating. 

Slipping Clutch. Slipping is the most common of clutch trou¬ 
bles. This is brought about in a cone clutch by oil, grease, or other 
slippery matter on the surface of the clutch, and can often be cured 
temporarily by throwing sand, dirt, or other matter on the clutch 
surface, although this is not recommended. Many times, the 
clutch leather or facing becomes so glazed that it slips without any 
oil or grease on it. In that case it is desirable to roughen the surface 
by taking the clutch out, cleaning the surface with kerosene and 
gasoline, and then roughing up the surface with a file or other 
similar tool. 


362 


GASOLINE AUTOMOBILES 


201 


In case it is not desired to take the clutch out, or when it is very 
inaccessible, the clutch surface may be roughened by fastening the 
clutch pedal in its extreme out position with some kind of a stick, 
cord, or wire, and then roughing the surface, as far in as it can be 
reached, with the end of a small saw, preferably of the keyhole type, 
about as shown in Fig. 155. Before starting this repair, it is well 
to soak the leather with neatsfoot oil, pouring this in the night 
before and allowing the leather to soak up as much of it as it will. 
This softens the leather and makes the roughening task lighter. 

Many drivers make the mistake of driving with the foot con¬ 
stantly on the clutch pedal. This wears the leather surface and 
helps it to glaze quickly. The constant rubbing, due to slipping 
it frequently, also makes the 
leather hard and dry. 

When a metal to metal, 
oiled clutch slips, the trouble 
usually is in the clutch spring 
which is too weak to hold the 
plates together. To remedy slip¬ 
ping with this type then, it is 
necessary to tighten up on the 
clutch spring adjustment. 

Clutch troubles are not al¬ 
ways so obvious. In one instance, 
the clutch slipped on a new car. In the shop, the clutch spider 
seemed perfect, also the spring, and properly adjusted, but to make 
sure, a new clutch was put in. Still the clutch slipped. To test it 
out still further, the linkage was disconnected right at the clutch 
and then it held perfectly, showing that the trouble was in the link¬ 
age. On examination one bushing was found to be such a tight fit 
that it would not allow the pedal to move freely enough to release 
fully. When this was relieved a little, the clutch acted all right. 

Handling Clutch Springs. Clutch springs, like valve springs, 
mentioned previously, are mean to handle and compress, the best 
way being to compress and hold them that way until needed. For 
this purpose, a rig similar to that described for valve springs should 
be made but of stiffer, stronger stock. A very good one can be 
made from two round plates, one small, and the other of larger 


SAW 


FLYWHEEL 



CLUTCH 

CONE 


Fig. 155. Method of Roughing-Up Clutch 
Leather with Saw 


363 
















202 


GASOLINE AUTOMOBILES 


diameter with a pair of L-shaped bolts through it. The spring is 
placed between the two with the ends of the L’s looped over the 
smaller plate, and then, by tightening the nuts on the bolts, the 
spring is gradually compressed. 

Fierce Clutch. A “fierce” clutch is one that does not take 
hold gradually, but grabs the moment the clutch pedal is released. 
In a metal disk clutch, this is caused by roughened plate surfaces 
and insufficient lubricant, so that instead of the plates twisting 
gradually across one another as the lubricant is squeezed out from 
between them, they catch at once and the car starts with a jerk. 
On a cone clutch, this fierceness is produced by too strong a spring, 
too large a clutching surface in combination with a very strong 

spring, or a hard or burned 
clutch surface, or both. 

Ford Clutch Troubles. 
There are now so many 
Fords in use that the aver¬ 
age repair man feels justified 
in making special apparatus 
or tools to save time or 
work in Ford repairs. For 
one thing, the clutch disk 
drum frequently needs re¬ 
moval and this is a difficult 
job. By means of a simple 
rigging, however, consisting 
of a plate and a few bolts, it can be taken off in a few moments and 
with little trouble. It will be noted from Fig. 156 that the rigging is 
but a modified form of wheel puller. It consists of a J-inch plate of 
steel with three holes drilled in it for three bolts. The two outside 
ones have T-head ends and have to be specially made, and made care¬ 
fully, as this T-head must slip through either one of the oval holes 
in the web of the drum. When this is done, it is straightened up 
so as to stand at right angles to the drum and is thus in a position 
to press firmly against the drum from the inside. There are nuts 
on the center bolt on both sides of the plate, the drawing showing 
only that on the outer end. When the T-bolts are in place, the 
center bolt, which is slightly pointed and preferably hardened on 



364 






















GASOLINE AUTOMOBILES 


203 


the end, is screwed down so as to come into contact with the end 
of the clutch shaft. After tightening this, the T-head bolts are 
tightened until they pull the drum off the shaft. 

Clutch Spinning. A trouble which is bothersome but not 
dangerous is clutch spinning. This is the name applied to the 
action of the male clutch member when it continues to rotate or 
spin after the clutch spring pressure has been released. With the 
male member connected up to the principal transmission shaft and 
gear, as is often the case, these members continue to rotate with it. 
This gives trouble mainly in gear shifting, for the member which is 
out of engagement is considered to be at rest or rapidly approaching 
that condition. When at rest, it is an easy matter to mesh another 
gear with this one; but when this one is rotating or spinning, it is 
not so easy, particularly for the novice. 

Clutch spinning may be caused (1) by a defect in the design, 
in which case little can be done with it; (2) by a defect in construc¬ 
tion—as in balancing, for instance, which can be corrected; or (3) 
it may be due to external causes, as for instance a bearing which has 
seized, due to a lack of lubricant, etc. 

In any case, the best and quickest remedy is a form of clutch 
spinning brake. This may consist simply of a small pad of leather, 
or metal covered with leather, so located on the frame members 
that the male drum touches against it when fully released. Or it 
may be something more elaborate as to size or construction, or both. 
On many modern cars, in fact on practically all good cars, some 
form of clutch spinning brake is fitted. Thus in Figs. 139 and 149, 
metal cones of small diameter are provided; in Fig. 140 is found 
something similar with two V-grooves; while Figs. 145 and 148 show 
flat concentric disks. 

TRANSMISSION 

Primarily, the clutch is used to allow the use of change-speed 
gearing; or, stated in the reverse way, the form of the transmission 
determines whether a clutch must be used or not, there being cases in 
which it is not used. Thus, where the frictional form of transmission 
is used, no clutch is necessary, the frictional disks acting as a clutch 
and rendering another one superfluous. So, too, with the form of 
transmission known as the planetary gear ,no master clutch is needed. 


365 


204 


GASOLINE AUTOMOBILES 


On the other hand, the reverse of this does not always hold. Any 
form of clutch may be used with the various other forms of transmis¬ 
sion, as the sliding gear; in fact, in actual practice every known kind 
of a clutch will be found coupled with the sliding-gear transmission. 

Classification. Broadly considered, there are five classes of 
transmissions used. In cases where the use of any one of these 
forms eliminates the final drive, this from its very nature does not 
alter the facts, but simply calls for a different and more detailed 
treatment. The five classes are: 

f Selective 
I Progressive 

(1) sliding gear ) Electrically operated 
I Air operated 


(2) 

(3) 

(4) 


(5) Miscellaneous 


Individual clutch 
Planetary or epicyclic 

Friction disk. Various spur and bevel arrangements 
Belt and cables 
Hydraulic 
Electric 
Combinations of two or more 

The features of the 1916 transmissions which stand out from 
previous years are: reduced sizes; simpler, lighter construction; 
greater compactness and greater accessibility. The smaller sizes 
have brought about the simplification and lighter weight, and in 
turn have been produced in answer to the popular demand for 

lighter weight cars. In 
part, simplification has 
been produced by unit 
power plants, now so 
popular. 

SLIDING GE4R 
General Method of 
Operation. Of the dif¬ 
ferent types of sliding 
gears, the first two sub¬ 
divisions are not very 
closely marked, but 
blend somewhat into one 



Fig. 157. Mercedes (German) 22-H. P. Selective 
Transmission 


366 


































GASOLINE AUTOMOBILES 205 

another. The only real difference between them is the method of 
operation, the names serving to indicate the distinctive characteris¬ 
tics. Thus, in a selective gearset, it is possible to “select” any 
one speed and change directly into it without going through any 
other.. So, too, in the progressive form of transmission the act of 
changing gears is a “progressive” one, from the lowest up to the 
highest, and vice versa. 

. Selective Type. With the selective method of changing gears, 
it is possible to make the change at once from any particular gear 
to the desired gear without passing through any other, Fig. 157. 
Of course, the car will 
not start on the high 
gear any more than in 
the other case, but shift¬ 
ing into low for starting 
purposes is but a single 
action, accomplished 
quicker than it can be 
told. So, too, when the 
car has been started, it 
can be allowed to attain 
quite a fair speed and the change to high made at once without going 
through the intermediate gears. 

Progressive Type. Progressive gears are said to operate on the 
Panhard system, called after the originator of the system. This 
method leads to a number of troublesome occurrences; thus, in stop¬ 
ping it is necessary to gear down through all the higher speeds into 
low. If this is not done, when it is next desired to start the car it 
will be necessary to start the engine, throw in the clutch, drop from 
the gear in mesh to the next lower, from that to the next, and so on 
down to low, throwing the clutch out and in for each change of 
speed. When first is reached, the car may be started. After 
starting, it is then necessary, in order to obtain any measurable 
speed with the car, to change back up the list, from low to second, 
from second to third, and so forth. In this way the progressive gear 
is disadvantageous, since its use means much gear shifting; but, on 
the other hand, the shifting is very easy for the novice to learn, as 
it is a continuous process, all in one direction. 


























206 


GASOLINE AUTOMOBILES 



In Fig. 158 is shown the Panhard transmission for a car of 22 
horsepower. This is a four-speed transmission, and to show graph¬ 
ically one big disadvantage claimed against this form as in favor 
of the selectively operated gears, refer again to Fig. 157. This 
represents the four-speed transmission used in the Mercedes cars 
of approximately equal power to the Panhard just described. The 
difference in the over-all length of the two is immediately noticeable, 
yet the only other difference is that the German cars are operated 
selectively and the Panhards progressively. Panhard and Mercedes 


Fig. 159. Cadillac Transmission and Housing 

have been consistent advocates of these two forms, the former 
adhering to its special type on a few models, even when this type 
passed out of popular favor. The latter, too, has always used the 
selective form of gear on all its cars, since the inception of this by 
Herr Maybach. In the United States, the progressive form has 
slowly but very surely gone out. 

Modern Selective Types. To present some modern selective 
types of gear boxes, and point out their various differences, advan¬ 
tages and disadvantages, refer to Fig. 159. This type shows the 
three-speed selective gear used on the Cadillac cars, this being but 





GASOLINE AUTOMOBILES 


207 


slightly modified from the type which has been used by this maker 
for three years. This change should be noted, however: the lay 
shaft, which formerly was on the same horizontal level as the main 
shaft, is now placed directly below it. This makes a higher but 
narrower gear box that is, instead of being wide and fairly flat, it 
is now high and narrow. The placing of the shifting levers on the 
cover, directly over the center, has aided in making the gearset more 
compact than formerly. In it there are two shifting gears, one gear 
carrying a set of dogs cut into its face, which mesh with a similar set 
on the main driving gear to give high speed, which is the direct drive. 
The gear portion of this member meshes with another gear for second. 



The second shifting member meshes with one gear on the lay shaft for 
low speed and with another on the third shaft for reverse. This last- 
named gear is at all times in mesh with the fourth lay-shaft gear, so 
that on reverse the drive is through five gears instead of four. On 
high gear the drive is through the dogs, the lay shaft being driven, 
of course, but silently, as it transmits no power. 

Driving Off the Lay Shaft. As will be noted, in all the modern 
gears presented, the drive is off the rear end of the main shaft, the 
lay shaft serving only as a medium for speed reduction. It will be 
noted also that in all the original forms first shown, the drive was off 
the lay shaft; that is, the engine drove one shaft, while the other 
drove the wheels. This form was widely used in the early days, in 




















































208 


GASOLINE AUTOMOBILES 



is shown in Fig. 160, this being of the three-speed selective type, the 
same as those previously shown. 























































































































GASOLINE AUTOMOBILES 


209 


Obviously, this construction makes it impossible to have a 
direct drive, and on all speeds the drive must be through gears. This 
makes all speeds noisy, which is the real reason why it has gone out 
of use. As will be noted in Fig. 160, this has both the shifting 
members on the main shaft, the gears on the lay shaft being of the 
bolted-on type. This is done to reduce manufacturing costs. Note 
the double-row ball bearing to take thrust at the driving end of the 
main shaft and the driven end of the lay shaft. 

Four-Speed Type with Direct Drive on High. One of the tend¬ 
encies of recent years has been the gradual change toward more 
speeds, as shown by the increasing use of four-speed gear boxes. 
Other indications of this have been the two-speed axle, which gave 
double the number of gear-box speeds, with the ordinary three-speed 
and reverse transmission; and the electric transmission, which 
affords seven forward and two reverse speeds. 

An excellent example of the four-speed selective gear is the 
Austin (English), shown in Fig. 161. As will be noted, the two 
shafts are set side by side, running entirely on ball bearings. A 
notable feature is the introduction of an extra bearing in the center 
of each shaft, which, with the web of the case, forms the bearing 
supports and practically divides the case into two parts. In addi¬ 
tion, an extra bearing-support will be noted on the main driving gear 
at the left. High speed is a direct drive by means of dogs on high 
gear and on the first shifter. For second, this is shifted to the right. 
For third, the second shifter is moved to the left; and for low, to the 
right. Reverse is gained by setting the second shifter in the neutral 
position as shown, and shifting another pair of gears beneath the 
third speed and the small end of the shifter. An interesting feature 
of this unit is the spherical ball joint at the drive nend and the trans¬ 
mission brake, which is outside of this, and which is supported from 
the sub-frame at that point. 

The form of final drive alters the construction of the trans¬ 
mission very materially. Formerly, when all final drives were of the 
double-chain form, it was customary to include the differential, 
bevel gears, and driving shafts in the gear box. Now that the chain 
has gone out, this construction is found only when the gear box is a 
unit with the rear axle. 

Just for comparison with the domestic product, the transmission 


210 


GASOLINE AUTOMOBILES 


of the Horch, a famous German car, is shown in Fig. 162. High 
speed is obtained with direct drive by meshing gears A and D, 
through a gear not shown, cut in the face of A. Second is 
obtained by the combination A, B, C, and E. Third is given by 
A, B, F, and G. Fourth is produced by A , B, II , and 7, while 
a still further movement to the right of this second train gives the 
reverse. Attention is specifically called to the device for throwing 
the lay shaft out of gear when the high speed is engaged, this 
resulting in no gears running on the direct drive, that is to say no 
gears meshing face to face. The result is an absolute lack of gear¬ 
box noises on high speed. High speed is effected by the final move¬ 
ment of the shifting rod to the left, which actuates the high gear. 


Fig. 162. Horch (German) Four-Speed Selective Transmission 



The partial worm engages a sector so pivoted in the middle as to 
slide the gear B to the right, and enough to throw it out of mesh 
with A , when the shaft is moved so as to introduce gear, or rather, 
jaw clutch D into its mate within A . 

Four-Speed Type with Direct Drive on Third . In all the trans¬ 
missions shown and described thus far, the direct drive has been the 
highest speed. By referring back to Fig. 144, which showed the 
Winton four-speed gear box, as well as the clutch, a point of difference 
will be seen. This has the direct drive on third speed, fourth being a 
geared-up speed for use only in emergencies, when the very highest 
rate of travel is required, and when a little noise more or less would 
make no difference. This arrangement of the direct drive and silent 
speed has long been a debated point, some designers favoring the 
type just shown with an over-geared speed for occasional use, while 


















GASOLINE AUTOMOBILES 


211 


the opponents of this say that this construction practically reduces 
the transmission to a three-speed basis, the fourth being so seldom 
used that it is practically negligible. They say, also, that the 
modern motor can attain a high enough speed on the one hand and is 
flexible enough on the other to permit its being used with the high- 
gear direct drive upon almost all occasions. 

Electrically Operated Gears. In substance, the electrically 
operated transmission has all the hand levers, rods, and other levers 
replaced by a series of push buttons. When it is desired to change 
speeds even before the actual change is necessary, in fact, the driver 
presses the button marked for the 
speed he thinks he will require. 

Then, when the actual need becomes 
apparent, he throws out the clutch 
and immediately drops it back again, 
all this forming but a single forward 
and back movement of the foot. 

During the slight interval while the 
clutch is out, the electrical connec¬ 
tions shift the gears automatically, 
so that when the clutch is let back, 
the gears are meshed ready to drive. 

Principle of Action. To explain 
this action briefly, the gears are 
moved by means of solenoid magnets, which are nothing more than 
coils of wire, through which an electric current from a convenient 
battery is allowed to pass. Through the center of each one of these 
coils passes an iron bar. When a current passes through the coil, 
it is converted into an electromagnet and draws the iron bar inward. 
As the other end of the bar is connected to the gear to be shifted, 
this movement of the bar shifts the gear. Consequently, when the 
button is pressed so that current flows through one of the coils, 
that action shifts the gear for which the button is marked. 

By referring to Fig. 163, this action will be made more clear. 
The diagram shows but one pair of gears to be meshed, and the 
battery, push button S, coil D, iron bar P, and clutch connection 
M are all shown as simply as possible. When button S is pressed, 
current through the coil D will draw the bar P and mesh the 



Fig. 163. Sketch Showing How a 
Solenoid Moves a Gear When 
Current Flows 











212 


GASOLINE AUTOMOBILES 


gears, as soon as the clutch has been thrown out, thereby closing 
the circuit at M. The application of this to an actual transmission 
is shown more in detail in Fig. 164. This shows the clutch pedal 



Fig. 164. Arrangement of the Solenoids and Pedal in the Vulcan Electric Gear Shift 


and its connection to the six solenoids necessary to produce four 
forward speeds, one reverse, and a neutral point. 

On the steering wheel. Fig. 165, the control group of six buttons 
will be noted on the small round plate at the center, with the addition of 
the horn button in the center. In Fig. 166 is another arrangement. 

In the 1916 forms of electric control systems, the buttons are 



grouped in one case; on the top of a small box about four or five inches 
square, which is placed on the steering post below the wheel in an¬ 
other on the dash, and in a third on a rod connecting post and dash. 
















































GASOLINE AUTOMOBILES 


213 


Pneumatic Shifting System. The pneumatic system of gear- 
shifting is along lines somewhat similar to the electric system, air 
under pressure being used to move the gears, instead of a hand lever 
and rod combination. For this purpose it is necessary to add to the 
car an air compressor, a tank to carry the compressed air, and what 
is called the “shift”—really a complicated valve and a series of 
plungers. The valve and plungers respond to a finger lever on the 
steering wheel, the same as the electric system responds to the but¬ 
tons, air being admitted behind the plungers, which move the gears 



Fig. 167. Form of Gear for Gasoline Railway Car 


as soon as the clutch is depressed. It is seen, therefore, that this 
system, like the electric shifter, permits the anticipation of the car’s 
needs. 

Railway Car Needs. All transmissions previously presented 
have had but one reverse. For gasoline railway cars, the inability 
to turn requires as many reverse speeds as forward, which means 
special gearing, as shown by Fig. 167. This is the type used by the 
Sheffield Car Company, Three Rivers, Michigan, in their gasoline- 
driven railway cars. The driving bevel, faintly seen at A, instead 


375 




214 


GASOLINE AUTOMOBILES 


of driving but one bevel, as is usual, drives two, C and D. Each 
one of these is free on the shaft, being bushed to reduce wear, but 
between the two is a sliding member B, with jaw clutches formed on 
both faces. This slides on a squared shaft, and the jaw clutches 
match jaw clutches formed in the inside face of the two driven 
bevels. When slid to the right, then, B engages with jaw clutches 
in gear D, and thus drives it. If, then, the gear box gives three 
speeds, all three may drive through this combination, giving the for¬ 
ward speeds. If it is desired to drive in the other direction, the 
clutch member B is slid out of mesh with D and into mesh with C, 
thus reversing the direction of motion and the direction of all speeds. 

Rear Axle Combinations. Aside from the railway form, the 
location of the transmission varies its form. The front location for 
the engine is now universal, but this cannot be said about the gear 
box. This unit, on the contrary, is placed in every conceivable 
position from that of an integral part of the engine rear end to a part 
of the rear axle and differential housing. 

INDIVIDUAL CLUTCH 

General Types Used. While the number of adherents to the 
individual clutch type of transmission is not as great as that of either 
the progressive or selective types of sliding gear, still it holds its 
own; and, in fact, as time passes, it gains adherents. In this form, 
all the gears are in mesh at all times, and what has been called 
“the barbarous and unmechanical” method of clashing gears is 
entirely done away with. The individual clutch type is operated 
on the selective plan; but, otherwise, has nothing in common with 
the latter. 

The forms of clutches used vary greatly, as might be expected. 
The following are in use today: jaw clutches (both two, and mul¬ 
tiple jaw); internal-external gears; multiple disk; cone; and friction 
clutches, other than the multiple-disk form. 

Using Internal Dogs. One type in which the gears are engaged 
by internal dogs, the gears being in mesh at all times, has four sets 
of gears, those on the main shaft being keyed or otherwise fixed to 
the shaft, while the gears on the jackshaft run idle except when the 
gear-shifting lever is moved forward to an engaging position, which 
movement throws an internal dog up into a slot inside the gear. 


376 


GASOLINE AUTOMOBILES 


215 


This makes the gear one with the shaft, and so, the power is trans¬ 
mitted. The dogs in the latest form of this transmission take the 
form of hardened and ground steel balls. 

Disk Type. Many of the early individual clutch types of trans¬ 
missions used disks, each gear having its own set and each set having 
sufficient surface to carry 
the whole power of the 
motor. While bulky, this 
had undeniable advan¬ 
tages, for it allowed start¬ 
ing on any gear. 

C ontr acting-Band 
Type. While advocates 
of disks are numerous, 
other devices do not lack 
friends. Fig. 168 shows Fig - 168< EaTly Form ° f Haynes Clutdl Gearset 
a form that, on the Haynes-Apperson cars, attained much popu¬ 
larity. In it the clutching action is produced by means of con¬ 
tracting bands,.working on large-diameter drums, the latter being 



keyed each to its own gear. The full explanation of the action is as 
follows: The engine drives the shaft A , upon which are mounted 
the gears C , D, E, and 
F. These are all perma¬ 
nently fixed to the shaft 
and rotate with it. Upon 
the driven shaft B are 
mounted another equal 
number of gears, mesh- £ 
ing with the former, but 
all loose upon the shaft, 

SO as to Spin idly. Fig. 169. Early Form of Winton Individual 

Bolted to each of the Clutch Transmission 

latter is a large drum, while close to it is a framing upon which is 
mounted a contracting band. The latter framing is keyed to the 
shaft, so that when it is rotated the shaft must turn with it. In 
action, then, when any speed was desired, the band was contracted 
until it seized the drum bolted to the gear which gave that speed, 
when the gear, drum, band, and framing all turned as a single piece. 






















































































216 


GASOLINE AUTOMOBILES 


Single-Disk Winton. Winton long advocated the individual 
clutch gear, his clutch taking the form of a single disk, pressed 
against the gear by means of numerous fingers, Fig. 169. A conical 
sliding piece, G or J, expanded the fingers pivoted on M and H, so 
that they pressed against the disk within the gears D, K, or N. 

Internal-External Gear Type. Many of the gears already given 
date back several years, but the gear illustrated in Fig. 170 is more 
modern, and is being used today by the International Motor Com¬ 
pany, New York City, and Allentown, Pennsylvania. 

The principle upon which this gear works, as shown by Fig. 170, 
is that of the internal-external gear. The gears which transmit the 



Fig. 170. Mack Commercial Car Individual Clutch Type of Gear Box 
Courtesy of International Motor Company, New York City and Allentown, Pennsylvania 


power are always in mesh. Each one of these is bushed and runs idly 
upon the main shaft. Contained within each and an integral part, is 
an internal gear of twenty-four teeth. Sliding on the squared shaft 
are four 24-tooth gears, these being specially built for easy engag¬ 
ing with the internally cut gears. 

To follow the letters placed on the parts of this gear, high speed 
is obtained by sliding the piece 2-C-31 forward into gear 2-C-34, 
which action swings the piece shown dotted beneath, so as to throw 
out clutch on the lay shaft 2-C-52. On high speed, the two gears 
locked together are the only ones to turn, all others being idle. The 
same piece, 2-C-31, when slid to the right meshes with the internal 


378 

































































GASOLINE AUTOMOBILES 


217 


gear of the second-speed pinion 2-0-160. This sliding member slides 
upon a squared shaft, so the drive is positive. The action of the third 
or slow speed, and reversed are the same as those just described, being 
produced by the shifting of the clutch member 2—0—66. Attention is 
called to the ball bearings used on this transmission, which are only 
remarkable when it is remembered that this is a commercial truck 
transmission. Students of automobile construction will find many 
interesting constructional details in this illustration, which is a repro¬ 
duction of the manufacturer’s working drawing. 

Still another similar form uses three cone clutches in the trans¬ 
mission, that for the high speed being augmented by a set of pins 
or dogs, which, as the clutch gradually takes hold, slip into an equal 
number of holes in the driven gear. In this way, the two are made 
as one, which makes slipping impossible, a very important feature. 

Transmission Operation. As has been pointed out previously, 
practically all transmissions operate all gears by means of a long hand 
lever, placed either at the side of the car or in the center, according 
to the location of the control. Even on planetary forms, still to be 
described, at least one of the various speeds is controlled by a hand 
lever. The electric and air shifting methods have made a start, and a 
good one, but until their number reaches a good many times what it 
is now, these types can only be considered as having started the 
push button development. 

Transmission Lubrication. A fairly heavy lubricant is gener¬ 
ally recommended for gear box use, either a special form of about the 
right consistency, or else a homemade mixture, about half-and-half, 
light oil and hard grease. Some firms recommend a graphite grease. 
In general, the lower part of the case should be filled to a point or 
level where the largest gears dip continuously. This will insure a 
constant agitation of the lubricant, which will thus get to all moving 
parts and surfaces. Having the lubricant too stiff is bad, because then 
the gears simply cut a path through it without moving the rest. 
This results in all other parts running practically dry. Too thin a 
lubricant or too much of it, will make a fairly heavy drag on the 
motor, which loss of power should be avoided. Gear-box lubricant 
generally is introduced in bulk by the removal of the cover, usually 
of a large size to allow of this. The outside parts carry their own 
grease and oil cups. 


379 


218 


GASOLINE AUTOMOBILES 


Transmission Bearings. By looking back at the various trans¬ 
missions shown, it will be noted that ball bearings are used most 
freely. Roller bearings in various forms are coming into use, as the 
shorter series, produced in the last couple of years, have shown 
designers that this type would produce a compact gear box, their 
size having previously limited their use. Plain bearings are not 
used at all on good cars. 

Transmission Adjustments. Few adjustments are needed in 
the modern gear box. However, provision for wear is made in the 
operating rods and levers, both within the case and without. In 
some cases the shafts may be slightly shifted endwise to secure 
better meshing of the gears after wear. Bearings, too, are arranged 
to shift slightly in an endwise direction, to take care of wear in other 
parts, not so much in the bearings themselves. 

PLANETARY GEARS 

Method of Action. The planetary, or epicyclic, form of gear¬ 
ing offers many advantages, but, strange to say, the American 
people, although inclined toward simplicity and cheapness in com¬ 
bination, will not have it in this form, and, as a consequence, this 
excellent gear-reducing means is fast losing favor. The principle 
upon which all planetaries work is as follows: Connected to the 
engine is the first gear of the train. The second is one of a series of 
several, these being pivoted in a drum, which may be held stationary 
by a brake band. The middle or third in the train, as well as the last 
or fourth, is connected to another gear, a driven gear, not a driver. 
Considering but a single rotating train—there usually are three or 
more—the last-named gears form the fifth and sixth in the whole 
train. Gears two, three, and four are all of different numbers of 
teeth, as well as the gears one, five, and six. Holding the band which 
holds the drum to which the gears are pivoted, allows each of them 
to rotate around its own axis, but not around the main shaft. This 
form of rotation gives one gear reduction. 

Holding another band holds another gear stationary and allows 
the three-gear unit to rotate around the main shaft as an axis, while 
at the same time it leaves them free to also rotate around their own 
axis. This produces another gear reduction. Another form which is 
popular in so far as planetary gears are popular, is that in which 


GASOLINE AUTOMOBILES 219 

internal, gears are substituted for one set of the planets, from which 
the device obtained its name. This does not complicate the device 
any, in fact, the only way in which it makes any change is in the 
manufacturing cost of the gear, internals costing more than spur 
gears. 

Ford Planetary Type. Ford has been a consistent user of the 
planetary gear, in fact, the simplicity and ease of operation of his 
well-known and widely used car is largely due to this use. The Ford 



transmission, which is of the all-spur-gear type, is shown in Fig. 171. 
This is operated by means of two pedals and a lever, one pedal 
working high and low speeds, while the other pedal controls the 
reverse. The first-named pedal, however, must be used in conjunc¬ 
tion with the forward movement of the hand lever which locks the 
high-speed clutch, seen in this figure at the right. 

Railway Planetary without Reverse. In Fig. 172 is seen a 
planetary gear without reverse, because its work called for all speeds 
in both directions. This necessitated the use of a bevel-gear reverse, 


381 
























































































220 


GASOLINE AUTOMOBILES 


through which the final drive was taken. As the drawing shows, this 
simplified the transmission very much. There is the crankshaft gear 
A near to the flywheel F, which gear is in mesh with a series of three 
pinions BB, two only being shown. The latter are made an integral 
part with other smaller pinions CC, which mesh with another gear D 
fast to the driven shaft G. The drum H holds the two ends of the 
shaft on which the planet pinions B and C rotate. This prevents 
them from turning about the main or crankshaft axis, but when 



Fig. 172. Two-Speed Planetary for Railway Cars 
Courtesy of Sheffield Car Company, Three Rivers, Michigan 

the engine is driving them they are forced to rotate on their own 
axis E. The result of this is to drive the final shaft G in the reduction 
ratio of the two pairs of gears A to B and C to D. Thus, suppose the 
gears to be of the following number of teeth, which is not far from the 
actual case: crankshaft gear A, 18 teeth; larger pinion B, 24 teeth; 
smaller pinion C, 15 teeth; final driven gear D, 27 teeth. If the 
crankshaft turns over, say, 1000 revolutions per minute, the pinion 
shaft will be turned 1000 times 18 divided by 24, or 750 revolutions. 
The smaller pinion also turns over 750 and imparts to the final gear 











































































GASOLINE AUTOMOBILES 


221 


a rotation of /50 times 15 divided by 27, or 417 revolutions per 
minute. This is the low speed. 

Now, to obtain the high speed , the sliding cone J at the left is 
moved over the expanding levers, which serve to push the whole 
system of gearing over against the flywheel, the disks L and M 
(running in oil) acting as a clutch, which finally takes hold, and the 
whole mechanism rotates as a unit, at crankshaft speed. 


FRICTION DISK 

Undoubtedly, when simplicity is sought, regardless of cost, the 
friction drive is the drive used. The cost with this form is not 
one of money, but rather of other 
things which must be sacrificed 
if friction drive is used. 

Spur Type. In the interest 
of simplicity, it may be said that 
the friction form of drive dis¬ 
penses with the clutch, being of 
itself both clutch and change- 
speed gear. The usual form which 
this takes is the single spur wheel 
contacting with another flat-face 
wheel. Since these must be at 
right angles, the car is nearly 
always a chain-driven one, the 



Fig. 173. Four-Disk Friction 
Transmission 


driving wheel being on the rear end of the crankshaft, and the 
driven shaft across the middle of the car. To secure a more cer¬ 
tain drive and at the same time obtain the differential action, the 
cross shaft is often fitted with a pair of wheels, contacting with 
opposite sides of the driver, and mounted upon two independent 
shafts. As this method causes the two driven shafts to turn in 
opposite directions, a gear is necessary at one end of one of them. 

The greatest feature of the friction drive is the multiplicity of 
speeds obtainable, these being infinite in number, since every dif¬ 
ferent position of the driven wheel on the driver results in a different 
ratio, and, consequently, a different speed. To obtain these various 
changes, the wheel which meets the other edge-on is usually arranged 
to be advanced up to and withdrawn from the wheel presenting the 





















222 


GASOLINE AUTOMOBILES 


flat surface. In action, a motion of translation is given to the wheel 
at the same time as the motion up to or away from the surface. This 
motion of translation changes its position, and consequently its 
speed. 

Over the three-wheel arrangement, the use of four possesses 
some undeniable advantages, particularly if the two parallel driv¬ 
ing wheels are arranged to drive the others in pairs. This achieves 
the result that the direction of rotation of the wheels is alike, and no 
intermediate gear to change the direction of one shaft is needed. 
In Fig. 173 it may be seen that the two cross shafts do not line up 

exactly, the one at the 
right being set slightly 
in front of the left one. 
This keeps the right- 
hand friction out of en¬ 
gagement with the rear 
driver, and the left out 
of contact with the for¬ 
ward driving wheel. The 
two driven wheels must 
be shifted together, or 
otherwise a different 
speed will be produced 
in the two rear wheels. 
A simplification of this 
utilizes the flywheel of 

Fig. 174. Friction Transmission with Bevels ^ engine as the for¬ 

ward driving disk. 

Bevel Type. Bevels have much to commend them as opposed 
to the spur friction wheel. They are found in combinations, such as 
a single pair of bevels, three, and in multiple combinations, without 
limit to the number. Fig. 174 shows the use of a single pair, but 
in combination with a flat face on one and a spur attached to the 
other, making the whole consist of four wheels in reality. This is 
the drive as used on the Metz cars, particularly their small com¬ 
mercial cars. 

In Fig. 175 is presented another combination—three bevels, 
one of them with a flat face and a spur, making really five wheels— 












































GASOLINE AUTOMOBILES 


223 


in which are many novel features, in that the spur wheel in every 
case takes the final drive, and also, in that a direct drive on the high 
gear is obtained by the use of a cone clutch on this spur and another 
with which it engages on 
the driving wheel. One 
bevel gives forward 
speeds, and through the 
other the various reverses 
are gained. 



Fig. 175. Friction Transmission with Three 
Sets of Bevels 


MISCELLANEOUS TYPES 

Freak Drives. What 
are termed the freak 
drives attract much at¬ 
tention from inventors, 
but little from hard- 
headed constructors. Thus, the belt drive was once advanced as 
the simple drive, yet it made no progress. Today there are few 
belt drives used in final driving in America, although a few are still 
made on the other side. There is [a French car, Fouillaron, of low 
price, with this drive, and a single-cylinder Italian car, the Otav, 
selling for the equivalent of $150, is |also so equipped. 

[Cable and Rope Drives. When cyclecars were first brought 
out and by many considered as destined to replace both the low- 
priced cars, on account 
of their still lower price 
and | simplicity, and mo¬ 
torcycles, because of their 
greater comfort, superior 
appearance, and greater 
carrying capacity, many 
of the simple drives were 
revived and applied to 
the cyclecars. The types 
used include the cable drive, which attracted much attention at 
one time in the motor buggy field, the rope drive, the flat belt, the 
V-belt, the cloth covered chain, and many others. With the col¬ 
lapse of the cyclecar boom, these went out of use. 











































224 


GASOLINE AUTOMOBILES 


Hydraulic Gear. Janney-Williams. The hydraulic transmis¬ 
sion has been advanced as a cure for all automobile troubles, rep- 



Fig. 177. General Scheme of Janney-Williams Hydraulic Gear 


resenting as it does the elimination of clutch, differential, and the 
driving mechanism. It consists of a pump to circulate the fluid, and 



Fig. 178. Manly Fluid Transmission with Multiple-Cylinder Arrangement 


one or two motors to be propelled by the same, usually attached to 
the rear wheels. In the Janney-Williams hydraulic gear, which has 






































GASOLINE AUTOMOBILES 


225 


been successfully used for some time in other fields, but has just 
recently been tried for automobiles in England, there are three 
similar pumps, one being used as a pump and the other two as 
motors. Fig. 176 shows a section through this and Fig. 177 the 
general arrangement of the drive, the engine end being the same as 
in any other case. By rotating the driving ring, shown inclined in 
Fig. 1/6, so that it assumes different angular positions, the throw 
of the small pistons, of which there are nine in all, is varied from 
zero up to a maximum. Since the action of the fluid in the motors 
connected to the wheels is opposite to this, it amounts to varying 
the speed, the number of changes being infinite, as in friction gearing. 

Manly . Another hydraulic drive of equal merit and of Ameri¬ 
can manufacture, is the Manly, Fig. 178 and Fig. 179. As is shown, 
this differs from the Jan- 
ney-Williams only in the 
form of the motors; the 
fluid and its use are the 
same in both cases. This 
drive has for its object, 
first, the securing of any 
desired speed of the 
driven shaft, either for¬ 
ward or backward, without 
changing the speed or di¬ 
rection of motion of the driving shaft; and second, of transmitting the 
power to a shaft, which is either in line with the driving shaft or which 
lies at any angle to the driving shaft and separated therefrom. It 
consists of a multicylinder pump —A and D being two of the cylinders 
with variable stroke, which is attached to the driving shaft, and 
one or more multicylinder motors—two being shown at B and C — 
having a fixed stroke, which are attached to the driven shaft K, 
together with pipe connections or passages E and F between them 
for transmitting the working field. The various cylinders, both of 
the pump and motors, radiate equidistantly from a central crank 
chamber, and the pistons or plungers are connected to a single crank 
pin, which is common to all. The fluid used is ordinary machine oil, 
the lubricating qualities of which, and its freedom from the danger of 
freezing, admirably fit it for such a purpose. When the system is 



Fig. 179. Section of Manly Drive 










226 


GASOLINE AUTOMOBILES 




once filled the oil is used over and over again, being in continuous 
circulation from pump to motor through one set of pipes or passages, 
and back again from motor to pump through another set. The 
stroke of the pump may be varied at will; that of the motor is fixed. 
The variation of the pump stroke is accomplished by a crank, on 


E lg. J.SU. uritisn inomson-Elouston Company's Uasolme-Electric Chassis. 

View from Above 

which is mounted an eccentric bushing. By revolving the bushing 
with reference to the crank its center line is brought into alignment 
with the center of the shaft, and when this position is reached no 
reciprocating motion is communicated to the pump plungers. The 
Manly is constructed under license by the American-La France Fire 


Fig. 181. British Thomson-Houston Gasoline-Electric Chassis. Side View 

Engine Company, Elmira, New York, and on very large trucks, and 
some of their unusually heavy fire apparatus has proven its worth. 

In recent years a number of hydraulic transmissions have been 
brought out, but all these face the fundamental difficulty that when 
the pump chamber is liquid tight the friction is excessive. 

















GASOLINE AUTOMOBILES 


227 



Pneumatic Drive. There has been some talk of a pneumatic 
drive also, this idea not being so far from the previous one of 
using liquids. In this scheme a large tank of compressed air is 
provided for the purpose of starting the engine, helping to get up 
speed quickly, and for use on hills when excess power is needful, or at 

least helpful. If used as planned, it 
would allow of the elimination of 
the reverse and would be utilized for 
braking as well, the present form of 
band brakes being replaced by air 
brakes. This is but a prospective 
scheme, never having been tried; 
yet in considering the future, it is 
worth more than a passing thought 
because of its latent possibilities. 

Electric Drive. 
To speak of an elec¬ 
tric drive sounds pe¬ 
culiar, yet that is what 
should be used for a 
final drive through the 
medium of electric 
motors. This form, 
spoken of abroad as the petrol-electric 
car , is attaining much headway there. 
It gains slowly, it is true, but, never¬ 
theless, surely—each year seeing one or 
more added to the already long list of 
successful cars in this category. To 
mention a few of these—Mercedes and 
Krieger are recognized as leading Ger¬ 
man makes, while Gem, Vate, and 
Auto-Mixte are of high rank in France, and Peiper, Hallford, Electro- 
mobile, Hart-Durnall, Thomson-Houston, and Silvertown, as well as 
others in England, not to forget Roland, Couple-Gear, and others 
in this country. All these have done good work in furthering the 
cause of the electric drive. In Fig. 181 and Fig. 182 are shown a 
plan and a side view of the most excellent gasoline-electric chassis 


Fig. 182. Section Showing Principle of 
Action of Mercedes Gasoline- 
Electric Drive 















228 


GASOLINE AUTOMOBILES 


built by the British Thomson-Houston Company. These are in 
service in London as motorbusses, in which service they have shown 
to good advantage. Fig. 182 shows a drawing of the construction 
of the wheels of the Mercedes gasoline-electric vehicle, in which the 
motors are carried within the wheels themselves. In this, the front 
wheels only are active. As shown in Fig. 183, they are readily 
disassembled in case of trouble on the road, not even a jack being 
necessary. This view also shows all the parts composing the motor 
within the wheel. 



Fig. 183. Mercedes Driving Wheel Disassembled 


Differing from this very markedly is the other prominent Ger¬ 
man advocate of mixed driving, as the gasoline-electric system is 
called. In this, the generator is coupled to the engine in the place 
ordinarily occupied by the flywheel and clutch, the armature, in fact, 
acting as a flywheel. Then the motors are set one on each side, 
directly in front of the rear wheels, which they drive through the 
medium of spur gears, the whole being enclosed to keep out dirt, keep 
in oil, and reduce noise to a minimum. 

On the whole, the electric drive is losing no ground, which, in 
these days of gasoline shaft-driven cars, is perhaps something gained. 
In fact, it might be said that it possesses so many advantages which 
are worth having, even at a sacrifice, and so few disadvantages, that 









GASOLINE AUTOMOBILES 


229 


one is safe in figuring that a few more years will see the number of 
these drives doubled and possibly trebled. 

Electric Transmissions. While the drives just discussed might 
be called electric drives and still be precise, the Owen magnetic car, 
which is constructed in New York City, makes use of an actual 
electric transmission, the Entz, at one time used in a Columbia 
chassis and previously spoken of. This is so arranged that all speed 
changing is done by a small finger lever on the steering wheel similar 
to the ordinary spark and throttle levers. The wiring formerly gave 
seven speeds forward and two reverse, but a later construction will 
probably give about twice this number. 


As is shown in Fig. 184, this consists of an electric generator, the 



Fig. 184. Drawing Showing Section through Owen Magnetic Transmission 

field magnet of which is connected to the engine crankshaft and takes 
the place of the flywheel, the armature being connected with the 
driving shaft. This transmits the turning effort of the engine by 
means of the current established in its circuit, due to the speed 
difference of its members on what constitutes the high speed. Any 
effort exerted by the engine on one member is transmitted, prac¬ 
tically without loss, to the other member or armature. The clutch- 
generator member makes a very elastic clutching and transmitting 
means, but cannot transmit more than the full torque of the engine. 

For higher torque, use is made of an electric motor, whose 
armature is mounted on the driving shaft and receives current from 
the first or clutch generator. 






































































230 


GASOLINE AUTOMOBILES 


In the figure the clutch generator is shown at the left, its field 
part marked FR, the field winding FW and the pole pieces PP. 
This portion rotates whenever the crankshaft revolves. Within it is 
the armature A, secured to the continuous shaft S, which is con¬ 
nected through the joint X with the driving shaft to the rear axle. 

The second part of the complete system is shown at the right, 
and is practically a duplicate of the clutch generator. Its armature 
Ai is carried on the same shaft 8, as armature A. Outside this is 
the usual field part with rings FR, windings FW, pole pieces and 
brushes B. 

• Field FR can revolve without any motion of A; in fact, it is by 
varying the relative speed of FR and A that the different speeds are 
obtained. For instance, on direct drive the generator is short- 
circuited on itself and carries armature A with it. Then, except for 
a slippage of 4 per cent or less, between the field FR and the arma¬ 
ture A, the wheels would be driven as fast as the latter rotated. 
Lower speeds are produced by making the slippage greater. Speed 
changing, as well as starting and braking, are accomplished by means 
of the finger lever on the steering wheel. In addition, the storage 
battery is charged at a 10-ampere rate. 

TRANSMISSION TROUBLES AND REPAIRS 

Noise in Gear Operation. One of the most common of trans¬ 
mission troubles is noise in the operation of the gears, generally a 
grinding sound. This is heard more in bevels than in spurs, but in 
old transmissions and on the lower speeds it is heard frequently. A 
good way to quiet old gears, after making sure that they are adjusted 
rightly and meshing correctly, is to use a thicker lubricant. If 
thick oil is being used, change to a half-oil half-grease mixture or 
preferably an all-grease mixture of fairly thick consistency. 

In this respect the repair jnan or amateur worker may take a 
leaf out of the book of second-hand car men, who are said to “load’ 5 
an old and very noisy transmission gear with a very thick almost 
hard grease in which is mixed some shavings, sawdust, cork, or 
similar deadening material. When this is done, a graphite grease is 
generally used, so that the shavings, cork, etc., would not show in 
case it was necessary to take off the gearbox cover. This material 
will fill up all the inequalities of the gears and shafts so that tern- 


392 


GASOLINE AUTOMOBILES 231 

porarily, everything fits more tightly, and in addition all the sound¬ 
ing-board, or echo, effect is taken out of the transmission case. 
This sounding-board effect is fully as important as the former, for 
many really insignificant noises are magnified, by poorly shaped 
gearcases, so as to appear very loud, indicating serious trouble which 
needs immediate attention, when such is really not the case. 

Another source of gearset noise is a shaft out of alignment, 
caused either by faulty setting, by worn or loose bearings, or by 
yielding or cracking of the case. If it is properly set at one end and 
is out at the other, the trouble will be more difficult to find and 


remedy. 


Heating. Heating is a common trouble, too, but usually this 
can be traced to lack of lubricant in an old car, of too large shafts 
or too small bearings in a new one. Sometimes the grease used will 



Fig. 185. Types of Gear Pullers 


cause heating, particularly when long runs are made with the trans¬ 
mission working hard. This is most noticeable when the grease or 
lubricant is of such a consistency that the gears simply cut holes in 
it but do not carry any around with them, or do not otherwise 
circulate the lubricant. This can be remedied by making it thicker 
so the gears will cut it better, by making it thinner so they will 
splash it more, or by changing the nature of it entirely to a form 
which is more sticky and will adhere more tightly. 

Gear Pullers. One of the principal necessities for transmission 
work is a form of gear puller. These are like wheel pullers, except 
that they are smaller and more compact. In Fig. 185, a pair of 
these are shown. The one at the left is very simple, consisting of a 
heavy square bar of iron which has been bent to form a modified U. 
Then, a heavy bolt is threaded into the back of this or bottom of 


393 










232 


GASOLINE AUTOMOBILES 


the U. This will be useful only on gears which are small enough to 
go in between the two sides of the puller, that is, between the sides 
of the U, which in use is slipped over the gear, the screw turned until 
it touches something solid as the end of the gear shaft, and then the 
turning continued until the gear is forced off. 

While not as simple as this, the form shown at the right has the 
advantages of handling much larger gears, and also of being adjust¬ 
able. As the sketch shows, this consists of a central member having 
slotted ends in which a pair of L-shaped ends or hooks are held by 
a pair of through bolts. Then there is a central working screw. To 
use, the hooks are set far enough apart to go over the gear, then 
slipped around it and hooked on the back. The central screw is 
turned up to the end of the shaft, and then the turning continued 
until the gear comes off. There are many modifications of these 
two, in fact practically every repair shop in the land has its own 
way of making gear or wheel pullers. At any rate, every shop 
should have one. 

Care in Diagnosis. |The repair man should use a great deal of 
care in doping out or diagnosing the trouble in a transmission, for 
frequently what appears at first to be at fault turns out to be all 
right; or else something is back of the first trouble which must be 
corrected before a remedy can be applied. Thus, recently, a repair 
man figured that a new gear was needed to repair a transmission. 
This was received from the factory three days later, and when he 
started to put it in, he found that a bearing was defective; in 
fact, the defective bearing caused the wear in the gear. This neces¬ 
sitated a further delay of three days in order to get a new bearing. 

Poor Gear Shifting. A common transmission trouble is poor 
gear shifting. This may be due to a number of different things. 
For one thing the edges of the gears may be burred so that the edges 
prevent easy meshing. When this is the case, any attempt to force 
the gears into mesh only burrs up more metal and makes the situa¬ 
tion worse. Whether this is the trouble can be determined very 
quickly and easily by removing the transmission cover and feeling 
of the gears with the bare hand; the burred edges can readily be 
distinguished. If this is the only fault, the transmission should be 
taken down, the gears taken out and placed in a vise, and the burrs 
removed with a cold chisel and file. 


394 


GASOLINE AUTOMOBILES 233 

Poor or worn bearings or a bent shaft or one not accurately 
machined may cause difficult shifting. If the bearings are worn, 
the difficulty of shifting will be accompanied by much noise, both 
in shifting and after. The bent shaft is more difficult to find and 
equally difficult to fix, a new shaft probably being the quickest and 
easiest way. 

Sometimes the control rods or levers bind or stick so that shift¬ 
ing is very difficult. In case the gears are difficult to “find” or will 
not stay in mesh, the fault may be in the shifter rod in the transmis¬ 
sion case.. This usually has notches to correspond to the various 
gear positions, with a steel wedge held down into these notches by 
means of a spring. The spring may have weakened, may have lost 
its temper, may have broken, or for some other reason failed to work. 
Or with the spring in good working condition, the edges of the 
grooves or notches may 
have worn to such an 
extent as to let the 
wedge slip out of, or 
over, them readily. 

Handy Spring Tool. 

In the Ford transmis¬ 
sion band assembly 
there are three springs, Fig ‘ 186 ' Handy Spring T ° o1 for Ford Assembly 
which it is difficult to assemble because of the trouble in holding 
so many things at once. To eliminate this trouble the tool shown 
in Fig. 186 can be constructed, this being made from flat bar stock. 
The handles, if they could be called that, are pivoted together and 
carry at one end a kind of flat jaw with three notches. When the 
two of these are squeezed together by means of the screw and 
handle at the other end, the flat plates will hold the three springs 
tightly enough so that all can be inserted in their proper positions 
at once, and by using but one hand. Tools of this kind, which save 
a great deal of the workman’s time and thus save both time and 
money for the owner of the car, should, and in fact do, distinguish 
the good well-equipped repair shop and garage from the old-fash¬ 
ioned kind which is only in the business for the money, and not 
too particular how to get it. 

In transmissions of the planetary type, there is little or no 







234 


GASOLINE AUTOMOBILES 


trouble except with the bands. If these are loose, the gears will 
not engage and the desired speed will not result. If they become 
soaked with grease, oil, or water, they will not work as well as if kept 
clean, and in the case of excessive grease, will slip continually. If 
the band lining becomes worn, it should be treated just as a brake 
lining is. When inspected for wear and found not badly worn but 
slippery, it may be cleaned in gasoline and then in kerosene, after 

which a saw, hacksaw, 
or coarse file may be used 
to roughen it. Some¬ 
times greasy bands can 
be fixed temporarily— 
say, enough to get the 
car to a place where tools, 
materials, and] facilities 
for doing the work are 
available—by sprinkling 
on powdered rosin or 
f u 1 le r ’ s earth. The 
former should be used 
sparingly because it will 
cause the band to bite 
or grab hold when forci¬ 
bly applied, and at times 
has been known to cut 
into and score a cast-iron drum. In general, as stated previously, 
planetary transmission bands should be handled in the same way as 
ordinary brake bands, as to lining and relining, roughness of surface, 
lubrication, etc. 

GEARS 

Since the whole subject of transmission concerns itself with 
gears, it will not be out of place to discuss the gears themselves 
and describe the many different kinds in use. Speaking broadly, 
the gears used may be classified according to the position of their 
axes, relative to one another. Thus we have axes parallel and in the 
same plane; parallel but not in the same plane; at right angles and in 
the same plane; at right angles and not in the same plane; at some 







GASOLINE AUTOMOBILES 


235 


other angle than a straight or a right angle and in the same plane; 
and the same, but not in one plane. These classes give us the forms 
of gear in common use,, viz, spur gears, bevel gears, helical gears, 
herringbone gears, spiral gears, and worm gears. 

Spur Gears. A spur gear is not only by far the most common 
kind of gear, but is also the easiest to describe, consisting as it does 
of a round flat disk with teeth cut in its circumference, i.e., around 
the periphery of the disk. The cutting of these teeth has had much 
to do with their universal use, since the very low cost of cutting the 
teeth, due to special machinery developed for that purpose, just 
about explains the matter. Formerly, the teeth were cut, one gear 
at a time, in the milling machine, this being practically a hand oper¬ 
ation, since all movements of the gear or cutter had to be made by. 
hand. Later, improvements made it possible to cut more than one 
gear at a time, which resulted in lowering the cost, but did not 
eliminate the hand work. 

Step by step special machinery was developed for this work, 
until finally a perfected machine was brought out which does all 
the work. With this machine, the workman places the cutter 
on the machine spindle, sets the gear blanks into position, and starts 
the machine, after which it goes on automatically cutting tooth 
after tooth to a correct shape, until the gear is finished, when the 
workman is again necessary to shut it off, and, after taking out the 
finished gears, put in a fresh supply of gear blanks. 

This machine, known as the Fellows gear shaper, Fig. 187, has 
reduced the manual labor of gear-cutting to such a point that it is 
possible for one man to operate, unassisted, from three to six machines 
at one time. Usually, these are placed together and located near the 
automatic machinery, a group of them being called a battery. By 
having a battery of five machines cared for by a single man v 
the cost of spur-gear cutting has been brought down to the abso¬ 
lute limit. 

Bevel Gears. Bevel gears, in which the shafts are at right 
angles and in the same plane, or in the same plane but not at right 
angles, are more difficult to cut and therefore less used. Their 
cutting is now done, like the spurs, in an automatic, or nearly auto¬ 
matic, machine, which requires little attention, but it does require 
more care than the spur-gear machine. Both spurs and bevels 


236 


GASOLINE AUTOMOBILES 


sometimes require a chamfered tooth-edge, spur gears as used in the 
Panhard or clash-gear transmission always being in need of it. This 
work was formerly done by hand, but now a special machine has been 
manufactured for this purpose. 

There are no real restrictions against the use of the spur and 
bevel, either or both being used interchangeably. Very often they 
are used in combinations, which appear peculiar, as the one shown 
in Fig. 188. This is the final drive and reduction gear of the Autocar 
commercial cars, made by the Autocar Company, Ardmore, Penn- 



Fig. 188. Combination of Gears in the Autocar Final Drive 


sylvania. In this it will be noticed the drive from the engine is to an 
intermediate shaft through bevels and final drive by spur gears. 

Helical and Herringbone Gears. In situations where quiet 
running is deemed necessary, the use of a helical gear frequently finds 
favor, since it accomplishes the desired result, although the cost of 
cutting is high. Of late, these have come into general use for cam¬ 
shaft drives and similar places. A pair of helical gears set so that 
the helices run in opposite directions, forms a herringbone gear. 
This is even more quiet in its action than the single helix, and pos- 







GASOLINE AUTOMOBILES 


237 



sesses other virtues as well. One well-known firm has adopted it for 
camshaft driving gear, and makes it, as described, to save cutting-cost, 
as the cost of cutting a true herringbone would be prohibitive. So, 
a pair of helical gears of opposite direction are set back to back and 
riveted or otherwise fastened together, forming a herringbone gear at 
a low cost. Both of these may be used when the two shafts are par¬ 
allel and in the same plane, but for cases where the shafts are neither 
in the same plane nor parallel, some form of spiral gear must be used. 


Spiral Gears. Spiral gears, as such, not being generally under¬ 
stood, and that variety of the spiral known as the worm gear being 
very simple and easily understood, the latter has attained much 
popularity within the past few years. This has been due in part to 
superior facilities for cutting correct worms and gears, but, in the 
main, to a superior knowledge of the principles upon which the worm 
works, and the things which spelled failure or success. Thus, one of 
the earliest experimenters in this line laid down the law that the 


Fig. 189. Hindley Worm Steering Gear for Heavy Trucks 


399 




238 


GASOLINE AUTOMOBILES 


rubbing velocity should not exceed 300 feet per minute if success was 
desired, or in rotary speed about 80 to 100 revolutions. For auto¬ 
mobile use, this was out of the question; but later experimenters 
found that these results only attached to the forms of gear used by 
the early workers, and did not apply to a strictly modern gear laid 
down on scientific principles. 

The mistake made was in the pitch angle of the worm, which 
was formerly made small, nothing over 15 degrees being attempted. 
This was the item that was at fault and caused this very useful 
and efficient mode of driving to fall into disuse. As soon as this 
fact was ascertained and larger pitch angles utilized, better results 
were attained, until with 20-degree angles, 700 feet per minute pitch¬ 
line velocity was attained, followed shortly by the use of even higher 
angles, resulting even more successfully. As the efficiency depends 



Fig. 190. Rear View of Timken Worm-Driven Rear Axle 
Courtesy of Timken-Detroit Axle Company, Detroit, Michigan 


directly upon the pitch angle, these changes brought the efficiency 
of this form of gearing from the former despised 30, 40, and some¬ 
times 50 per cent up to 87, 88, and even 90 per cent, thus putting it 
on a par with any but the very best of spur gears, and above bevel 
gearing. In fact, in the light of modern knowledge of worm gears, 
it could easily be said without departing from the truth that it 
is possible to obtain from this form an efficiency of 93 per cent. In 
automobile work it has been used mostly for steering gears and final 
drives. For the former its irreversible quality is brought out, while 
for the latter this must be made subordinate to a great reduction, 
which may be attained in a very small, compact space. Many 
modern machines make use of worm gears: as Jeffery, and the Baker, 
Detroit, Hupp-Yeats, and Woods electrics; Pierce, Packard, Loco¬ 
mobile, Mack, Atterbury, Blair, Chase, Gramm, G. M. C., Hulburt, 


400 


GASOLINE AUTOMOBILES 


239 


Moreland, Standard, Sterling, and other trucks; Dennis (English) 
busses and trucks, and Greenwood and Batley (English) trucks. 
Among those using the spiral bevel may be noted Packard, Cadillac, 
Reo, Stearns-Knight, Yelie, Kline, Apperson, Buick, Chalmers, 
Chandler, Cole, Haynes, Hupmobile, Jackson, King, Locomobile, and 



Fig. 191. Worm Gear Applied to Rear Axle Drive of Touring Car 

many others. Figs. 189,190,191, and 193 show applications of the 
worm, and Fig. 192 shows a separate detail of a worm as used on a 
prominent truck. 

Spiral Bevels . The spiral bevel is a new development, having 
been brought out in 1914 as a compromise between the worm and the 
straight bevel. As such, it is supposed to have practically all the 
advantages of both, except that it does not afford the great speed 



Fig. 192. Worm Used on Locomobile Trucks 
Courtesy of Locomobile Company of America, Bridgeport, Connecticut 


reduction that can be accomplished with a worm in the same space, 
being more like the bevel in this respect. 

Worm Gears. Progress in the application of worm gears for 
rear-axle use has been considerable in the last few years. In one 
respect, at least, designers have found it an advantage. The top 


401 






240 


GASOLINE AUTOMOBILES 


position for the worm was not much used at first, as it was thought 
impossible for it to receive sufficient lubricant there. Consequently, 
it was always placed in the bottom position, which cut down the 
clearance considerably; in fact, in this position the clearance was 
less than with the ordinary bevel. With the proof that the worm 
could be lubricated in a satisfactory manner in the top position, the 
majority of them are so placed, thus converting what was formerly 
a disadvantage into an advantage, for in the upper position the 
clearance is greater than with bevel gears. This is shown quite 
clearly in Fig. 190, where it will be noted that the worm-gear housing 
in the center is actually higher than are the brake drums at either 

end of the axle. This too, despite 
the fact that a truss rod passes 
beneath the center of the axle. For 
heavy trucks especially, and for 
pleasure electric cars, the worm 
has proved an ideal drive. [In these 
situations there is the condition 
of high engine or electric-motor 
speed, coupled with low vehicle 
speed requirements, which necessi¬ 
tate a considerable reduction. As 
pointed out, the worm gives this 
in a small space. 

For 1916, the very apparent 
tendency in final drives is toward 
spiral bevels for pleasure cars and worms for electrics and trucks. 
The tendency toward spirals is very great, amounting practically 
to a landslide, 57 per cent using it against 10 for 1915. The devel¬ 
opment of special machinery for cutting these gears and the under¬ 
standing of their use has brought this about. In the truck field 
there has been a similar movement toward the worm, due to similar 
causes. 



BRAKES 

Function of Brake. Next to proper power, applied through the 
correct form of gearing, and its final suitable drive to the road wheels, 
nothing is of more importance than the ability to stop the vehicle 


402 



GASOLINE AUTOMOBILES 


241 


at will. The first step is to have a machine that will function cor¬ 
rectly, that is run at will, and following that it is necessary to be 
able to bring it to a stop, both to avoid danger and otherwise. The 
medium through which this is done, and which ordinarily suffices, 
is the shutting-off of the source of power—in this case, the gasoline 
and the spark which is used to ignite its vapor. This will not always 
suffice, however, for the ordinary car possesses the ability to run at a 
speed of 40 miles per hour or upward, and weighs from 2000 pounds 
(one ton) upward to 4000 pounds (two tons). This combination 
makes for a large force of inertia, which will result in the car running 
for many yards, even hundreds of yards, after the power is shut off. 
So it is that we must have a mechanical means of absorbing this 
inertia, or of snubbing the forward movement of the car. This is the 

function of the brakes, as fitted 
to the modern car. 

Engine as a Brake. Although 
disregarded in any summary of 
brakes, the engine is the best 
brake possible, granting that the 
driver knows how to get the best 
results without doing any dam¬ 
age. The ordinary engine has a 
compression of from 60 pounds to 
70 pounds per square inch, which is practically the pressure available 
when it is used as a brake. Since this is more than any other type 
or form of brake will yield, its usefulness is self-evident. 

Classification. Brakes are usually divided into two classes, 
differing mainly in location: the internal expanding and the external 
contracting. To this a third class should be added, because it partakes 
of the nature of both, yet differs from each one. This is the railway 
type of brake with removable shoes of metal, differing from the band 
type in that no attempt,is made to cover the whole or even the greater 
part of the circular surface, but simply a small portion of it, against 
which a shoe is forced with a very high pressure. Both the other types 
are subject to division into other classes, the first into three subdivi¬ 
sions according to operating means: cam, toggle, and scissors action. 

In addition, brakes are generally divided according to their loca¬ 
tion, as shaft and rear axle. The former, it might be added, having 



Fig. 194. Brake on Main Shaft of 
Benz (German) Car 


403 




242 


GASOLINE AUTOMOBILES 


virtually gone out of use. With worm driving there is a marked 
tendency back to the shaft brake, particularly on motor trucks. 
Again, in the last few years, some work has been done with 
pneumatic, hydraulic, and electric forms of brake. With air under 
pressure, or water, or electricity needed elsewhere on the car for 
starting or for other purposes, it is a simple matter to utilize the same 
agency for braking as well, providing such use does not add too 
much complication, and at the same time will give a superior method 
of snubbing the forward movement of the car. In case none of these 



Fig. 195. Benz Countershaft Brakes for Chain-Driven Cars 


advantages are realized, there will be no particular advantage in 
adding new forms of brake. 

External=Contracting Brakes. This class of brakes is subject 
to but two divisions: single- and double-acting. In the first, an end 
of a simple band is anchored at some external point, while the other, 
or free end, is pulled. This results in the anchorage sustaining as 
much pull as is given to the operating end, that is, all pull is trans¬ 
mitted directly to the anchorage. This disadvantage has resulted 
in this form becoming nearly obsolete. 

Any brake of the true double-acting type will work equally well 
acting forward or backward. Fig. 194, the Benz differential brake, 


404 










GASOLINE AUTOMOBILES 


243 


shows this clearly. The external band is hung from the main frame 
by means of a stout link, which is free to turn. Now, the band itself 
is of very thin sheet steel, lined with some form of non-burnable belting, 
dhe ends carry drop forgings, to which are attached the operating 
levers. These are so shaped that the pull is evenly divided between 
the two sides of the band. This will be made apparent by considering 
that a pull on the lever H will result in two motions, neither one 
complete, since each depends upon the other. First, there will be a 
motion of the upper band end B about the extremity of the lower one 
as a pivot, followed by a movement of the lower end, pivot and all, 
about B as a second pivot point. These two motions result in a double 



Fig. 196. Internal-Expanding Brake of the Hotchkiss 
(French) Car 


clamping action, which is supposed to distribute evenly over the 
surface. In order to insure the latter, the lining is grooved or divided 
into sections. 

Usually, chain-driven cars have a different brake location from a 
car with shaft drive. The former have three sets of brakes: one on 
the main shaft, one pair on the countershaft, and another pair on 
the rear wheels. 

Internal=Expanding Brakes. While the contracting-band brake 
is well thought of, the internal-expanding form is rapidly displacing it 
for the reason that experienced drivers think more of it. In Fig. 196 
is shown a foreign idea of an expanding band, this being a brake 


405 




244 


GASOLINE AUTOMOBILES 




from the French Hotchkiss, built by the famous gun makers. This 
particular brake is from the four-cylinder, 16-horsepower car and 


Fig. 197. Peerless Rear Axle Brake 


possesses a pair of very wide shoes, which are expanded by means of 
a lever and toggle arrangement, and give very positive action. 

A considerable number of foreign cars, which are used in moun¬ 
tainous countries, show a method 
of cooling the brake drums by 
means of external cooling flanges. 
In some makes, even a water 
drip is provided for extremely 
hilly country. 

More modern practice shows 
no tendency to place all of the 
eggs in one basket, both forms 
of brake being employed together 
and upon the same car, usually 
also upon the same brake drum, 
one set working upon the exte¬ 
rior, while the other works upon 
Fig. 198. Timken Double Rear-Axle Brake the ^side. In Fig. 197, which 

shows the rear-axle brakes of the 
larger cars, made by the Peerless Motor Car Company, Cleveland, 
Ohio, this is plain to be seen, both the brakes being shown, although 
the drum upon which they work has been removed. The parts are 






GASOLINE AUTOMOBILES 


245 


all named so as to be self-explanatory. In this, as is usual, the inner or 
expanding band is operated by a cam. In the brake sets put out by 
the Timken Roller Bearing Company, Canton, Ohio, in connection 
with their bearings and axles, the toggle action is used, Fig. 198. The 
constructional drawings, Fig. 199 and Fig. 200, showing the brakes 
used on the Reo car, manufactured by the Reo Motor Car Company, 
Lansing, Michigan, indicate that this firm is partial to the cam for 
brake operation, since these are used for both internal and external 
brakes, the internal form having a split link connected to the toggle, 
while the external has a link movement in contracting much like that 



Fig. 199. Section Showing Construction Fig. 200. Drawing Showing Method of 

of Reo Brakes Operating Reo Brakes 

Courtesy of Reo Motor Car Company, Lansing, Michigan 


of the Benz form, which is shown in Fig. 194 and is there explained 
in detail. 

In general, however, when both brakes are placed on the rear 
wheels, one external and of the contracting-band type, and the other 
internal and of the expanding-shoe form, modern practice calls for a 
cam to operate the latter, operating directly upon the ends of the two 
halves of the shoe, while levers operate the band so as to get a double 
contracting motion. 

Some modern brakes may be seen in Figs. 201, 202, and 203. 
The first named shows a system such as just described; the second 


















246 


GASOLINE AUTOMOBILES 


shows a stiff metal shoe in both types; and the last a pair of shoes 
set side by side. In addition, the last-named includes a new thought, 
in that the brake shoes are floated on their supporting pins as shown. 
This makes the bearing of the shoes certain when expanded against 
every portion of the drum, as the shoes can “float” until they fit 
exactly. 

Double Brake Drum for Safety. A very important feature is 
pointed out by Fig. 201, namely that of safety. Where both brakes 
work on a common drum, one inside and the other outside, the con- 
t tinuous use of the service brake (whether internal or external) heats 



Fig. 201. Double Brake Drum Used on Locomobile Cars 


up the drum to such an extent that when an emergency arises calling 
for the application of the other brake it will not grip on the hot 
drum, being thoroughly heated itself. The double drum allows air 
circulation and constant cooling. 

Principle of Brake Operation. The principle of brake operation 
is perhaps made most clear by a little excursion into the design of a 
set of brakes. The master formula for this is 

Wv 2 

"~2f 

in which K represents the energy of the moving mass, W its weight, 
v its velocity in feet per second, and g the acceleration due to gravity, 


K = 













GASOLINE AUTOMOBILES 


247 



Fig. 202. Brakes and Rear Construction of Pierce Cars 
Courtesy of Pierce-Arrow Motor Car Company, Buffalo, New York 



Fig. 203. Side-by-Side Arrangement of Brakes on American Rear Axle 
Courtesy of American Ball Bearing Company, Cleveland, Ohio 


AOQ 





































































































































248 


GASOLINE AUTOMOBILES 


or 32.2 feet per second. Now when the velocity of the moving mass 
W is expressed in miles per hour (F) any value for the speed can be 
substituted for v by the use of the expression v 2 = F 2 X (1.465) 2 . 
Substituting for W, the weight of a vehicle, such as 2,240 pounds, 
when V is 20 miles per hour, gives 29,920 foot-pounds of energy. 
Since distance in which the brakes will act is of value, it may be 
found by introducing into this formula two factors, the proportion 
of the total weight which the braking wheels will bear, and the 
coefficient of friction between the road surface and the rubber tires. 



Fig. 204. Layout of a Brake-Operating System in Which Cables Are Used 


The former factor may be taken as tV of the whole weight of the 
car, while the coefficient of friction has the value .60. Including 
these in the expression, it takes the form 


Z _ TFF 2 X.0334 

kw 

in which l is the distance in which a braking effort sufficient to slide 
the wheels would stop the car; k is the coefficient of friction; and w 
is tV of the weight of the car. This gives 37.1 feet for the value of 
l for the vehicle figured above and moving at the same speed. 






























GASOLINE AUTOMOBILES 


249 


In proportioning the parts, it will be necessary to know the 
pull on the band, which is equal to 



Fig. 205. Exterior of the Motor which Forms the 
Central Unit of the Hartford Electric Brake 
Courtesy of Hartford Suspension Company, Jersey 
City, New Jersey 


p =few = ^^X.0344 


and this for the car and speed 
as before, works out to 806 
pounds. Using a material in 
which the strength was 60,000 
pounds per square inch and a 
factor of safety of 6, the sec¬ 
tional area at the weakest 
point should be 


Area = 


806X6 

60,000 


= .0806 square inch 


If round iron were to be used, f inch diameter would be safe, while 
in a flat section, such as the band itself, re inch by If inch would be 

sufficient, as would also ^ by 
1 inch. 

Methods of Brake Opera¬ 
tion. While it is generally 
thought that round iron rods 
are the universal means of 
brake operation, such is not the 
case. Many brakes on excel¬ 
lent cars are worked, as the 
illustrations show, by means 
of cables. This idea is. even 
carried so far that brakes have 
been fitted to operate through 
the medium of ropes. Chains 
of small diameter have also been used, as well as combinations 
of rods, chains, cables and ropes. 

A lever-operated braking system of a well-known medium- 
priced car is shown in the outline sketch, Fig. 204. In this system the 
forward part of each half is worked by rods, both moved by means of 
pedals, but the latter, or rear, part of each half is actuated by means 



Fig. 206. Hand Lever on the Steering Post for 
Operating the Hartford Electric Brake 









250 


GASOLINE AUTOMOBILES 


of cables. These have one advantage over rods in a situation like 
this, the diagonal pull with a stiff rod might in time act to pull the 
brakes sideways off their respective brake drums. The cable being 
more flexible, there is less danger of this. 

Fully as important as the operating means, is the matter of 
equalizing the pull so that the same force is exerted upon both wheels 
at once. This action is influential in causing side-slip or skidding, 
which may result fatally. To equalize-the force was one reason for 
the use of cables, although the more up-to-date way is to attach the 
operating lever to the center of a long bar, to the extremities of which 
the brakes themselves are fastened. 

A pull on the bar is then divided 
into two different pulls on the 
brakes, the division being made 
automatically and according to 
their respective needs. This is an 
important point and one that 
should be looked after in the pur¬ 
chase of a new car. 

Brake Adjustments. In recent 
years much of the brake improve¬ 
ment has been along the line of 
making adjustments easier and of 
making the adjusting parts more accessible. This can be noted in 
such case as Locomobile, Fig. 201, where the special adjusting handle 
on the brake is carried to such a height as to make the turning of it 
an easy matter. Similarly, on Pierce, Fig. 202, it will be noted that 
there is provision for increasing or decreasing the closeness of the 
shoes to the drum, which is easily accessible. 

Brake Lubrication. As for the actual brake surfaces, there is no 
such thing as lubrication; the surfaces should be kept as dry and 
clean as possible. If grease or oil gets out from the axle or other 
lubricated parts onto them, there is sure to be trouble. The operating 
rods and levers, however, should have fairly careful lubrication, for 
which purpose the best makers provide grease or oil cups at all vital 
points. If these be neglected, a connection may stick, so that when 
an emergency arises the brake will not act properly and an accident 
may result. 



Fig. 207. Wiring Diagram for the Hart¬ 
ford Electric Brake 












GASOLINE AUTOMOBILES 


251 


Recent Developments. In the last few years, the only new 
ideas advanced in the way of brakes concern front-wheel braking 
and electric brakes. The former were used quite extensively abroad 
in 1913, but in 1914 seemed to drop back, this, too, despite the fact 
that the Grand Prix race of the latter year showed in a marked 
manner the need for and special application of front-wheel brakes to 
racing and high-speed cars. It is freely predicted that they will 
come back strong in 1916 and 1917. 

Electric Brakes. A very efficient and compact brake, appli¬ 
cable with a small amount of work to any chassis having a storage 
battery, is the Hartford, shown in Fig. 205, while Fig. 206 shows the 
operating lever as it is placed beneath the steering wheel, and Fig. 
207 shows the wiring diagram. This consists in substance of a small 
reversible electric motor, to which is attached a 100 to 1 worm reduc¬ 
tion. Attached to this is a cable, which is fastened to the usual 
brake equalizer. Turning the current into the motor from the stor¬ 
age battery rotates it, winds up the cable and applies the brake. The 
complete outfit weighs but 35 pounds. The motor has a slipping 
clutch set to operate at 1000 pounds pull, at which it draws 40 
amperes of current from the battery for two-fifths of a second. In 
use, it replaces the emergency hand-operating lever, and is said to be 
able to pull a heavy car going 50 miles an hour down to less than 15 
in a distance of less than 35 feet. The pull is so great that the 
brake drums are oiled to prevent heating and possible seizing. 

Whatever advantages may develop in the use of this, it is certain 
that the next few years will see considerable improvement in braking, 
so that a greater force may be applied more quickly, and thus act 
to prevent a large part of the accidents for which automobile owners 
and drivers are now unjustly blamed. 

BRAKE TROUBLES AND REPAIRS 

Dragging Brakes. Probably the first trouble in the way of 
brakes is dragging, that is, braking surface constantly in contact 
with the brake drum. This should not be the case; usually springs 
are provided to hold the brake bands off the drums. Look for these 
springs and see if they are in good condition. Or one or both of 
the brake bands may be bent so that at a single point the band 
touches the drum. 


252 


GASOLINE AUTOMOBILES 


Another kind of dragging is that in which the brakes are adjusted 
too tightly—so tightly in fact that they are working all the time. 
In operating the car, there will be a noticeable lack of power and 
speed, while the rear axle will heat constantly. This can be detected 
by raising either rear wheel or both by means of a jack, a quick 
lifting arrangement, or a crane, and then spinning the wheels. If 
the brakes are dragging, they will not turn freely. 

All that is needed to remedy this trouble is a better adjustment. 
For the new man, however, it is a nice little trick to adjust a pair of 
brakes so that they will take hold the instant the foot touches the 
pedal, that they will apply exactly the same pressure on the two 
wheels, and yet will not run so loose as to rattle or so tight as to drag. 

Dummy Brake Drum Useful. Where a great deal of brake 
work is to be done, particularly in a shop where the greater part of 

the cars are of one make, 
and the brakes consequently, 
all of one size, a great deal 
of time and trouble can be 
saved by having a set of test 
drums. An ordinary brake 
drum with a section cut out 
so that the action inside may 
be observed, is all that is 
necessary, except that it should be mounted suitably. As shown in 
Fig. 208, it is well to fit a pair of handles to the brake drum to assist 
in turning the drum when the adjustment is being made. The real 
saving consists"of the work which is saved in putting on and taking off 
the heavy and bulky wheel each time when the adjustment is changed. 
The test drum is put on instead, and being small and light, and 
equipped with handles, it is easily and quickly lifted on and off. 
This enables the workman to make a better and more accurate 
adjustment than he would when the heavy wheel had to be handled, 
while the cut-out section enables him to see the inside working also, 
and thus correct any defects or troubles at this point. 

Eliminating Noises. Many times the brake rods and levers 
wear just enough to rattle and make a noise when running over 
rough roads or cobblestone pavements, but hardly enough to war¬ 
rant replacing them. The replacement depends on the accuracy 



Fig. 208. Dummy Brake Drum for Adjustment 
Work 














GASOLINE AUTOMOBILES 


253 


with which they work, the age and value of the car, and the attitude 
of the owner. In a case where the owner does not desire to replace 
rattling rods, this can be corrected by means of springs, winding 
with tape, string, etc. 

If the rod crosses a frame cross member or is near any other 
metal part and its length or looseness at the ends is such that it can 
be shaken into contact there, a rattle will result at that point. This 
can be remedied or rather deadened by wrapping one part or the 
other. For this purpose, string or twine can be used as on a base¬ 
ball bat or tennis racket handle, winding it together closely so as to 
make a continuous covering. Tire or similar tape may also be util¬ 
ized. When this is done, it is necessary to lap one layer partly over 
the next in order to keep the whole tight and neat. It has the 
additional advantage of giving a greater thickness and thus greater 
resistance to wear. If none of these remedies are available, or are 
sufficient, burlap in strips or other cloth may be used, putting this 
on in overlapping layers the same as the tape. 

The springs should be put on in such a way as to take up the 
lost motion and hold the worn parts closer together. The rattle 
occurs when the movement of the car alternately separates and pulls 
together the two parts, a noise occurring at each motion. The 
spring should be put on so as to oppose this motion, acting really 
as a new bushing or pin, the pull coming first upon the spring and then 
upon the bushing or pin pulled up tight. 






> ■ 





































. 






































' 












































" 
























REVIEW QUESTIONS 


417 











REVIEW QUESTIONS 

ON THE SUBJECT OF 

EXPLOSION MOTORS 


1. Name and describe the essential parts of an explosion 
motor. 

2. Name the various accessories necessary to the operation 
of an explosion motor. 

3. How is the fuel gotten from the fuel tank into the engine 
cylinder and how is it exploded? 

4. Describe (a) the four-stroke cycle; (b) the two-stroke 

cycle. 

5. Explain the essential points of difference between the 
motors used in automobiles, boats, motorcycles, aeroplanes, and 
stationary work. 

6. Explain and give reasons for six-cylinder firing arrange¬ 
ments. 

7. What are the advantages and disadvantages of four- 
cylinder and six-cylinder motors? Compare the two types. 

8. Explain what knowledge may be secured from an indi¬ 
cator and manograph diagram and to what purpose it may be put. 
Also explain how to make use of the diagram in finding the i.h.p. 

9. Assume that Fig. 47 is the diagram from a four-cylinder 
four-cycle motor, 107.6 lb. m.c.p., 650 r.p.m., 4i-inch stroke, di¬ 
inch cylinder diameter, 90 per cent mechanical efficiency. Deter¬ 
mine (a) i.h.p. and (b) b.h.p. 

10. Explain fully the effect of scavenging. 

11. Explain all points of difference between compression in 
the two'-stroke cycle and the four-stroke cycle. 

12. Why does increased compression pressure increase the 
efficiency of an engine? 



EXPLOSION MOTORS 


13. Suppose the clearance space in an engine becomes 
reduced 20 per cent. Explain the effect produced on the engine 
by this reduction. 

14. (a) Suppose the mixture is too rich and the amount of air 
in it is increased, giving a perfect mixture. Explain the effect of 
this change and give indicator diagrams, (b) Suppose another 
change is made, giving a very weak mixture. Explain the result. 

15. State the advantages and disadvantages of the two-cycle 
and the four-cycle engine. 

16. From what is gasoline secured and how is it obtained? 

17. Give a short description of the manograph and of its 
working. 

18. A certain motor is called a 30-horse-power motor. Tell 
in your own words just what you understand by this. 

19. A brake test is made on a two-cylinder two-cycle motor. 
The following data is taken: Revolutions per minute 900; length 
of brake arm 30 inches; load on scales to balance brake arms 4 
pounds; total load on scales with load applied 30 pounds 4 ounces. 
Determine b.h.p. 

20. State Roberts’ formula for calculating the horse-power of 
a gas engine. 


REVIEW QUESTIONS 

ON THE SUBJECT OF 

GASOLINE AUTOMOBILES 

PART I 


1. Give very briefly the most important elements in the 
historical development of motor-driven vehicles. 

2. Give the probable nature of future changes, if any, in the 
methods of cooling the engine; in the valve action. 

3. What is meant by “streamline” form of automobile 
bodies? What is the particular advantage of this type? 

4. Give the construction and action of a silent chain. 

5. What are the advantages of the revolving cylinder type 
of motor? Why can it dispense with a flywheel? 

6. Give the characteristics of three types of valves. 

7. What are the essentials of a water-cooling system in con¬ 
nection with an automobile motor? 

8. What is the usual construction of the “radiator”? Give 
the reason for the use of this form. 

9. What is meant by thermosiphon circulation? 

10. Give briefly the methods of cooling an engine by air. 

11. Describe the characteristics of a reservoir system of lubri¬ 
cation; of a splash system. 

12. Describe the ideal condition of a bearing for proper lubri¬ 
cation. 

13. What are the features and advantages of roller bearings? 

14. What is meant by an “annular ball bearing”? 

15. Compare the virtues of roller and ball bearings. J 

16. Sketch a high-tension ignition system. 

17. Sketch a low-tension ignition system. 

18. Explain the action of a master vibrator. 


421 



REVIEW QUESTIONS 

ON THE SUBJECT OF 

GASOLINE AUTOMOBILES 

PART II 


1. What is a cam; what is its function on an automobile 
engine; and how are cams named? 

2. In timing the valves of automobile engines, to what are 
all angles referred? 

3. Give an average set of timing angles. 

4. Describe the method of laying out a cam using these 
angles. 

5. Describe the action of the sliding sleeves in the Knight 
engine; the rotary sleeve in the Ledru engine. 

6. Describe and give the action of the surface carbureter, 
the filtering carbureter, and the spraying carbureter. 

7. Describe the Senrab carbureter. 

8. Mention some of the different types of throttle valves, 
and the name of the maker using each kind. 

9. How does the modern float differ from the earliest form? 
Describe its action in some one case. 

10. Give some of the methods of supplying heat to the vapor¬ 
izing chamber, and the reason for doing this. 

11. Give the arguments in favor of and against the auxiliary 
air valve. Describe the usual form. 

12. How many standpipes or fuel nozzles are ordinarily used 
in carbureters? Mention some makes which use more and the 
number used in each case. 

13. When the engine does not start on the first turn of the 
crank, what is the prime source of trouble to investigate, and how 
do you go about it? 



REVIEW QUESTIONS 

ON THE SUBJECT OF 

GASOLINE AUTOMOBILES 

PART III 


1. How many different forms of clutches are there? Name 

them. 

2. What is the necessity for a clutch? Give three reasons? 

3. Give an essential point in a design of a clutch, considering 
(a) the spring; ( b ) the lining; (c) gradual engagement. 

4. What are the two specific necessities of a cone clutch, and 
how does the angularity affect its action? 

5. Describe a cone clutch, giving a complete explanation of 
spring pressure and power transmitted, using the following data: 

(1) Horsepower 20; speed 1000 revolutions per min.; average radius 
of cone 8 in.; coefficient of friction .25; angle of clutch (0) 12 deg. 

(2) 1000 r.p.m.; average radius 7 in.; coefficient of friction .22; 
cone angle 14 deg.; spring pressure 200 lb. 

6. Mention the name and the maker of a band clutch; 
describe the clutch, referring particularly to (1) arrangement of 
band; (2) arrangement of spring; and (3) operating means. 

7. Give the formula for the pull necessary to stop a car. 
What is its value if coefficient of friction is .20, weight of car 2500 
lb., road wheels 36 in. diameter, and brake drum 14 in. diameter? 

8. Mention the name and maker of an expanding-band 
clutch; describe the clutch, referring to (1) spring; (2) band; and 

(3) operating means. 

9. How does the Warner clutch differ from the expanding 
band? Describe it. 

10. Select a true multiple-disk clutch, and describe it in detail, 
referring particularly to (a) number of fixed plates and arrange- 



GASOLINE AUTOMOBILES 


ment of plates; ( b ) number of free plates and arrangement of them; 
( c ) housing of plates; (d) oiling provision; and (e) spring. 

11. Give in brief the principle of the hydraulic clutch; the 
magnetic clutch. 

12. How many classes of transmission are there, and what 
are they? Which one is most used and why? 

13. Discuss electric gear shifting. 

14. What clutch is used in the Winton? 

15. What are the advantages of planetary transmissions? 
Describe one. 

16. What is the main limitation of the planetary gear? 

17. Name the advantages of friction driving. 

18. Describe the drive using an example with all spurs; one 
with all bevels; and one with both spurs and bevels. 

19. Name and describe an electric driving gear, and give its 
advantages. 

20. Name the forms of gearing used in automobiles. 

21. Which form is most used? Which least, and why? 

22. What form or forms are selected for quiet running? 

23. What item made early worm gears a failure, and later 
ones successful? What is its usual value? 

24. What are the forms of brakes and their subdivisions? 

25. Name and describe one each of the principal forms. 

26. What is the usual number of brakes fitted (a) to a chain- 
driven car; (6) to a shaft-driven car? 

27. Design the brake rods, as to diameter of stock, of a car 
described as follows: weight 2500 lb., maximum speed 40 miles 
per hour, tensile strength of material 50,000 lb., and factor of 
safety 6. 

28. Figure also the distance in which this would stop the 
above car; the distance if the speed were increased to 50 miles per 
hour. 


INDEX 


425 






INDEX 


The page numbers of this volume will be found at the bottom of the pages; 
the numbers at the toy refer only to the section. 



Page 

A 

Aeronautical motors 

24 

Air-cooling system 

204 

air jacket 

205 

blowing 

205 

flanges and fins 

204 

Air jacket 

205 

Alcohol fuel 

83 

American Ball Bearing Company 409 

Anderson Electric Company 

237 

Annular ball bearing 

222 

Anti-freezing solution 

203 

Anzani motor (French) 

193 

Argyll carbureter 

306 

Argyll disk clutch 

351 

Austin Automobile Company 

347 

Austin Motor Company (British) 345, 370 

Autocar Company 19 ; 

, 168, 398 

Automobile motors 

18 

valves 

19 

Auxiliary air valve 

299 

Axles 

180, 237 

I-beam 

237 

pressed-steel 

238 

tubular 

238 

Axle housing 

179 

B 

Ball auxiliary valve 

300 

Ball bearings 

221 

Band clutch 

342 

contracting 

342 

expanding 

344 

Batteries 

176, 210 

Bayard cone clutch 

337 

Bearings 

219 

ball 

221 

different requirements, for 

219 

plain 

219 

Note.—For page numbers see foot of pages. 


Bearings (continued) 

Page 

roller 

220 

Belt and cable transmissions 

385 

Benz brake 

403, 404 

Benz carbureter 

289, 308 

Benz cone clutch 

338 

Benzol fuel 

85 

Bevel gears 

397 

Blowers and fans 

205 

Body, vehicle 

249 

interchangeable 

257 

pleasure 

249 

truck 

256 

Bonnet 

181 

Bosch magneto 

210 

Brakes 

180, 240 

controls for 

241 

double drums for 

408 

facings for 

240 

forms of 

240, 403 

function of 

402 

operation of 

411 

principle of operation 

408 

recent developments in 

413 

troubles and repairs 

413 

Brake horsepower 

88 

Brake trouble 

413 

adjustment, drum jig for 

414 

dragging 

413 

noise 

414 

Briscoe eight-cylinder motor 

269 

Browne carbureter 

312 

Brown two-stroke motor (English) 20 

B.T.U. values of fuels 

C 

82 

Cable drive 

Cadillac Motor Car Company 

385 

45, 183, 202, 213, 

352, 368 


427 



2 


INDEX 


Page 

Cams 259 

design of 264 

function of 259 

location of, influence of 268 

manufacture of 270 

setting 261 

Camshaft 176, 270 

Carbureter, float-feed 289 

adjustment, improvements in 290 

features, new 318 

systems, details of 295 

troubles 322 

Carbureter systems 295 

auxiliary air valve, use of 299 

ball type (Grouvelle and 

Arquembourg) 300 

elements of, usual 299 

heavy-fuel, necessity for 299 

by-pass type 310 

Browne 310 

double-nozzle type 308 

Locomobile 311 

Saurer 310 

Zenith 309 

fuel-spray regulation 295 

complicated system (Longue- 

mare) 296 

simple system (Ford) 298 

inlet pipe, location in 302 

kerosene and heavy-fuel types 314 
Harroun 317 

Holley 314 

miscellaneous 315 

Senrab 318 

new features of 318 

double carbureters 320 

heavy-fuel vaporization 319 

higher mounting 320 

horizontal outlet 318 

Master carbureter 321 

multiple nozzles 320 

quick starting 320 

standard practice in 303 

Argyll 306 

Benz 308 

Daimler 308 

Decauville 308 



Page 

Carbureter systems (continued) 

standard practice in 


De Dion 

304 

Edwards 

305 

Siddeley 

307 

Venturi tube mixing chamber 302 

water jacketing in 

299 

Carbureter troubles 

322 

adjustment 

325 

needle-valve stem 

323 

starting 

322 

strainer 

323 

throttle 

324 

Carburetion 

175, 206 

Carpentier manograph 

57, 58 

Chalmers overhead valve gear 268 

Change-speed gears 

226 

individual-clutch 

228 

planetary 

226 

sliding 

226 

Circulating-water control (Cadillac) 202 

Clutch 

36, 224, 335 

bearings 

361 f 

forms 

335 

band 

226, 342 

cone 

224, 335 

disk 

225, 344 

hydraulic 

356 

magnetic 

358 

operation of 

359 

removal 

362 

requirements 

340 

troubles 

362 

Clutch trouble 

362 

Ford 

364 

grabbing 

364 

slipping 

362 

spinning 

365 

springs 

363 

Coil, ignition 

31, 176, 208 

Coil spring 

235 

Cone clutch 

224, 335 

double and triple 

337 

reversed 

336 

single 

335 

Connecting rod 

188 

Construction elements 

175 


Note .— For page numbers see foot of pages. 



INDEX 


3 




Page 

Construction elements (continued) 

clutch group 


178 

engine group 


175 

final-drive group 


179 

frame group 


181 

steering group 


180 

transmission group 


178 

Contact breaker 


50, 208 

Contracting-band clutch 


342 

Cooling systems 

177, 196, 204 

Crank arrangement and firing order 36 

Crank effort, theory of 


41 

effect of dead centers 


44 

eight-cylinder motor 


43 

four-cylinder motor 


42 

one-cylinder motor 


41 

six-cylinder motor 


42 

twelve-cylinder motor 


44 

two-cylinder motor 


41 

Crankshaft 

41, 

, 176, 189 

Crosby indicator 


53, 54 

Cross-connecting rod 


180, 245 

Crude-oil fuel 


83 

Cyclecar drives 


385 

Cycles of explosion motors 


13 

four-stroke 


14 

six-stroke 


17 

two-stroke 


16 

Cylinders 


176 

arrangements 


39 

lubrication 


212, 287 

multiplication of 


183 

numbering 


31 

ratings, in 


94 

relation to engine parts 


176 

wear 


288 

types of casting 


185 

D 



Daimler carbureter 


308 

Darracq rotating-valve motor (French) 194 

Decauville carbureter 


305 

De Dion carbureter 


289, 304 

Delivered horsepower 


88 

Demountable tires 


244 

Detroit multiple oiler 


214 

Development of the automobile 

162 

American progress in, history of 164 

Note .— For page numbers see foot of pages. 


Page 

Development of the automobile (con¬ 


tinued 

bicycle’s influence on 163 

early steam-vehicle 163 

European pioneers in 163 

Diehl Manufacturing Company 94 

Differential 180, 233 

Disk clutch 225, 344 

clutch and brake combination 348 

conical-surface 355 

dry 350 

facings for 352 

flat 347 

floating facing 353 

multiple 225 

single 226, 347 

Distributor 31 

Dorris clutch mechanism 360 

Double-chain drive 179, 231 

Driving shaft 179, 229 

Duryea gasoline vehicle, early 165 

E 

Edwards carbureter 305 

Electric drive 389 

Electric dynamometer 90 

Electric lighting-starting system 246 

control connections 247 

starting pinion 247 

units 246 

wiring 246 

Electric transmission 228, 389 

status of, present 389 

types of 389 

Mercedes system 390 

Owen magnetic system 391 

Thomson-Houston system 389 

Electrically operated gears 228, 373 

“Electrine” fuel 85 

Elmore two-cycle motor 20 

Enger Motor Car Company 46 

Engine, power-production elements of 182 
connecting rods 188 

cylinders 185 

operating cycle 182 

pistons 188 

valve mechanism 190 

Entz electric transmission 391 


4 INDEX 



Page 


Page 

Excelsior motorcycle motor 


24 

Friction-disk transmission 

233, 383 

Exhaust manifold 


176 

bevel type 

384 

Exhaust system 


176 

field of application 

233 

velocity factors in 


71 

spur type 

383 

Explosion motors 

11 

-96 

Fuel gage 

331 

cycle of operation of 


13 

Fuel mixture, explosibility of 

86 

details of construction and opera- 


Fuel tank 

175, 327 

tion 


25 

Fuels for explosion motors 

80 

elementary principles 


11 

alcohol 

83 

fuel mixture 


86 

petroleum products 

81 

fuels 


80 

unusual forms 

85 

historical interest, of 


. 12 

Fuel-supply system 

175, 327 

De Rochas’ theory 


13 

feeding 

327 

first practical (Lenoir) engine 

12 

pipes and connections 

330 

Otto engine 


12 

tank 

327 

horsepower, calculation of 


87 

troubles 

331 

stationary service 


47 

Fuel-system trouble 

331 

thermodynamics of 


52 

gravity flow, failure of 

331 

types for various purposes 


18 

line obstruction 

332 

F 



lock 

332 

Fairbanks-Morse stationary engine 49-51 

G 


Fans 

202, 

205 

Gaggenau piston-valve carbureter 292 

Fellows’ gear shaper 


396 

Gas friction 

72 

Fiat marine motor (Italian) 


191 

Gasoline automobiles 

160-415 

Final-drive system 

179, 

229 

air cooling 

204 

differential gears 

180, 

233 

bearings 

219 

types of 


229 

bodies 

249 

universal joints 

179, 

229 

brakes 

402 

Fire engine, motor 


255 

carbureters 

289 

Flanges and fins, cooling 


204 

carburetion 

206 

Float, carbureter 


295 

clutch 

334 

Flywheel 


178 

development of 

162 

Ford Motor Car Company 



electric lighting and starting 

246 

171, 187, 227, 230, 237, 

297, 

381 

engine elements 

182 

Four-cycle motors, details of 


25 

construction features 

175 

clutch 


36 

fuel supply 

327 

cooling system 


36 

gears 

396 

crank and firing arrangements 

36 

ignition 

207 

crank effort, theory of 


41 

lubrication 

211 

ignition 


31 

running-gear elements 

234 

lubrication 


35 

transmission elements 

224 

power exerted against pistons 


45 

transmission types 

365 

valves 


25 

valve gears 

259 

valve timing 


29 

water cooling 

196 

Frame, chassis 

181, 

234 

Gasoline fuel 

81 

Franklin air-cooled motor 


204 

solid form 

86 


Note.—For page numbers see foot of pages. 


430 


INDEX 


5 



Page 

Gear transmission 

366 

individual clutch 

376 

planetary 

380 

sliding 

366 

Gearbox 

179, 226 

Gearset 

179, 226 

gears 

226 

lever shifting, for 

179 

magnetic control of 

228 

Gears 

396 

bevel 

397 

helical and herringbone 

398 

spiral 

399 

spiral-bevel 

231, 401 

spur 

397 

warm 

401 

Goodyear tires 

242 

Gravity-feed lubrication 

214 

Gregoire aviation motor (French) 

198 

Grouvelle and Arquembourg carbu- 

reter 

301 

H 


Half-time shaft 

195 

Harroun kerosine carbureter 

317 

Hartford electric brake 

413 

Haynes Automobile Company 


166, 169, 

265, 377 

Hele-Shaw disk clutch 

354 

Helical and herringbone gears 

398 

High-tension ignition 

209 

Hindley worm gear 

399 

Holley kerosene carbureter 

314 

Hood 

181 

Horch selective transmission 

372 

Horizontal-opposed engine 

19 

Horsepower, calculation of 

87 

brake horsepower 

88 

estimating motor horsepower 

90 

indicated horsepower 

87 

mechanical efficiency 

88 

rating 

93 

Hospitalier manograph 

58 

Hotchkiss internal expanding brake 405 

Hyatt roller bearing 

221 

Hydraulic (oil operating) clutch 

356 

eccentric type 

358 

gear type 

357 

Note.—For page numbers see foot of pages. 


Page 

Hydraulic transmission 234, 386 

Manly system 387 

Janney-Williams system 386 

I 

Ignition 31, 176, 207 

high-tension 209 

low-tension 208 

magneto 210 

typical system of 31 

Indicated horsepower 87 

Indicator 52 

cards 65, 69, 70 

Individual-clutch transmission gears 376 
Inlet and exhaust valves 176 

Inlet manifold 176 

Internal-cooling system 205 

Interchangeable bodies 257 

J 

Janney-Williams hydraulic drive 386 

Johnson carbureter 33 

K 

Kerosene carbureters 314 

Kerosene fuel 83 

Kissel Motor Car Company 250 

Knight sleeve-valve engine, the 280 

^st by R.A.C. of England 281 

L 

Lanchester disk clutch and brake 348 

Leaf spring 235' 

Ledru sleeve-valve motor (French) 277 
Lighting system 246. 

Longuemare carbureter 296 

Locomobile Company of America 

251, 264, 311, 354, 401, 408 
Low-tension ignition 208 

Lubrication system 35 

distinction between internal and 

external 211 

essential conditions in 218 

external 215 

internal 212 

Lunkenheimer grease cup 215 

M 

Mack individual clutch transmission 378 
Magnetic clutch 358 

centrifugal drag 359 

friction engagement 358 


6 


INDEX 


Page 

Magnetos 210 

Make-and-break ignition 50 

igniter 50 

spark coil 51 

wiring diagram 51 

Manly hydraulic drive 387 

Manograph 55 

cards 73 

Marine motors 22 

Master carbureter 321 

Maudslay gearset 227 

Maudslay motor (English) 22 

Maybach float-feed carbureter 290 

Mechanical efficiency 88 

Mercedes disk wheels 240 

Mercedes gasoline-electric drive 389 

Mercedes selective transmission 366 

Metz friction transmission 384 

Military truck (French) 256 

Moline-Knight motor 192 

Mors contracting-band clutch 342 

Motor repairs, general 284 

cylinder head 284 

piston 286 

Motor trouble 284 

cylinder heads 284 

pistons 286 

valves 272 

Motorcycle motors 22 

Muffler 176 

Multiple-disk clutch 225 

N 

Naphtha fuel 83 

Naphthalene solid fuel 85 

National Motor Vehicle Company 185 
Needle valves 293 

Nordyke-Marmon Company 208 

North Chicago Machine Company 358 

O 

Oakland Motor Car Company 250 

Oils and greases 216 

Oil tank 177 

Omnibus 254 

Osborn sliding-sleeve valve motion 278 
Otto four-stroke cycle, the 60 

diagrams 60, 64, 78 


Note.—For page numbers see foot of pages. 


Page 

Otto four-stroke cycle, the (continued) 60 


ideal operation 

60 

practical operation 

64 

Owen magnetic transmission 

391 

P 

Packard Motor Car Company 

167 

Pambla hydraulic clutch 

358 

Panhard disk clutch 

349 

Panhard progressive transmission 367 

Peerless hub brakes 

406 

Peugeot cam mechanism 

270 

Pierce-Arrow Motor Car Company 

212, 236, 248, 

254, 409 

Pistons 

188, 285 

lightening 

286 

lubrication 

212, 287 

oversize, use of 

288 

replacing jig for 

285 

Planetary-gear transmission 

380 

Pneumatic drive, possibilities of 

389 

Pneumatic gear shifting 

375 

Poppet valve 

190 

Ports 

72 

Pressure-feed lubrication 

212 

Primer 1 

177 

Progressive transmission 

367 

Prony brake 

89 

Pump cooling system 

200 

R 

Radiator 

177, 199 

Rating 

93 

Rayfield carbureter 

15 

Rear axle 

180 

Renault motor (French) 

201 

Reo Motor Car Company 

25, 28 

Reversed-cone clutch 

336, 407 

Rims, demountable 

243 

Roberts two-cycle motor 

284 

Roller bearings 

169 

Rotating valve 

194, 283 

functions, separation of 

283 

Running gear, elements of 

234 

axles 

237 

brakes 

240 

demountable rims 

243 


432 


INDEX 


7 



Page 


Page 

Running gear, elements of (continued) 

Steering gear 

245 

frame 

234 

irreversible 

245 

shock absorbers 

236 

lever 

245 

springs 

235 

wheel 

245 

steering gear 

245 

Steering system 

180 

tires 

241 

Stevens-Duryea Company 

173 

wheels 

238 

Stewart vacuum gasoline-feed service 329 

S 


Stilson hydraulic clutch 

357 

S.A.E. formula (former A.L.A.M.) 94 

Strainer 

176 

Saurer carbureter 

310 

Streamline body 

250 

Scavenging 

205 

Stromberg carbureter 

291 

two-cycle 

79 

Studebaker Automobile Company 186, 338 

Seagrave pumping engine 

255 

Subframe 

181 

Selective transmission 

367 

Surface carbureter 

289 

Senrab carbureter 

318 

T 


Shaft drive 

179, 229 

Tables 


Sheffield Car Company 

375, 382 

effects of clearance 

68 

Shock absorber 

236 

explosion-motor fuels 

82 

Siddeley carbureter 

307 

timing regulation (American) 

261 

Sight feed 

177 

timing regulation (French) 

260 

Silent chain 

196, 233 

R.A.C. (British) test of Knight 


Sleeve valve 

277 

engine 

281 

rotating, worm-actuated (Ledru) 278 

Thermodynamics of explosion motor 

52 

sliding, double eccentric-actuated 

analysis of ideal Otto cycle 

60 

(Knight) 

280 

exhaust-gas friction 

72 

sliding, single eccentric-actuated 

four-stroke (Otto) cycle in practice 64 

(Osborn) 

279 

indicators 

52 

Sliding gears 

226 

large valve ports 

12 

Sliding gear transmission 

366 

manograph 

55 

Sliding sleeve valves 

193 

manograph cards 

73 

Sliding valves 

193 

two-cycle operation 

77 

Smalley two-cycle motor 

16, 48 

Thermosiphon cooling systems 

201 

Spark levers 

180 

Thomson-Houston Company (British) 388 

Spark plug 

176 

Thordarson Electrical Manufacturing 


Spiral bevel gear 

231, 401 

Company 

51 

Spiral gears 

230, 399 

Throttle lever 

180 

Splash lubrication 

214 

Throttle valve 

292 

Sprague Electric Works 

92 

Timken-Detroit Axle Company 


Spring 

235 

230, 231, 400, 

406 

coil 

235 

Timken roller bearing 

220 

leaf 

235 

Tires 

241 

Spur gears 

397 

cushion 

243 

Stationary service engines 

47 

demountable rims, on 

243 

four-cycle 

49 

pneumatic 

241 

two-cycle 

47 

Torque tube 

179 

Starting system 

246 

Transmission elements 

224 

Stearns-Knight motor 

23, 184 

clutch 178, 

224 


Note.—For page numbers see foot of pages. 



433 


8 


INDEX 



Page 


Page 

Transmission elements (continued) 

Valve mechanism 

190 

final drive 

179, 229 

actuation of 

195 

gearset 

226 

enclosure of 

191 

Transmission system 

365 

poppet 

190 

forms, principal 

366 

rotating 

194 

troubles and repairs 

392 

* sleeve 

193 

Transmission trouble 

392 

slide 

193 

diagnosis of 

394 

Valve repairing 

272 

gear puller 

393 

noisy tappet, quieting 

272 

gear shifting 

394 

removal of valve 

273 

heating 

393 

slotting for key 

276 

lubricant, consistency of 

, 393 

spring removal 

273 

noisy operation 

392 

compressor 

274 

planetary transmission band 

396 

tension, valve 

275 

Troubles and repairs 

272 

stretching and tempering springs 275 

brakes 

413 

Valve timing 

29 

carbureter 

322 

two-cycle 

78 

clutch 

362 

Vaporizer, types of 

289 

fuel system 

331 

early 

289 

motor 

272, 284 

modern 

290 

transmission 

392 

Venturi tube mixing chamber 

302 

Truck, dumping 

254 

Vulcan electric gear shift 

374 

Two-cycle operation 

77 

W 


charge 

77 

Water jacket 

177, 299 

diagram 

77 

Water-ccoling system 

196 

reversibility 

79 

anti-freezing solutions 

203 

scavenging 

79 

circulation 

200 

summary 

80 

fan 

202 

valve timing 

78 

radiator and piping 

199 

u 


water jackets 

196 

Underpan 

181 

Watt’s diagram 

53 

Unit power plant 

182 

Welding in automobile repair shops 99-158 

Universal joint 

179, 229 

Wheels 

180, 238 



demountable 

244 

V 


disk 

239 

Valve arrangements 

19 

spring, fallacy of 

242 

opposite sides 

21 

wire 

239 

overhead 

21 

wood 

238 

overhead shaft drive 

22 

Wildi carbureter 

303 

push-rod operated 

24, 25, 46 

Willys-Overland Automobile Com- 

sliding sleeve 

23 

pany 

247, 280 

two-cycle “valveless” 

18, 20, 47 

Winton Motor Car Company 


Valve gear, gasoline engine 

259 

225, 350, 377 

cams, use of 

259 

Wolseley aviation motor (English) 197 

repairing of 

272 

Worm gears 

401 

rotary valve 

283 

Z 


sleeve valve 

277 

Zenith carbureter 

309, 319 

Note.—For page numbers see foot of panes. 

A 7 l^f 




















s ** J . S /\ o' J 

r -A » ^ 

V 6 



<>x V 

OQT 


c v 



\ 



X <V V** * °/ - V' 

,v .m ^ ■% # - * 

^ ^ T> 

Ov^ ^r> ° ^ ^ o o 

^ \ -.■vvv > ^ % , 

V O •/ o _ . ^ ,(V y *t , 

1 “ * **o_ .o^ , « " '■ * <,> * * ’ vi> 


2 




& V 


\ V 



A 


s V V ^ 

V « V 1 * * o. 


V 

oo x 

° - A| 

m%b 

s ^ 

^ 4 

N 

A A,. 


<r 

Wlfw " 

\° o. 

x\ 

X}- 

y 

.y 




V 



//A " 

/ / .A / 


^ (X 


.*> , 0 ° ' c o 'i, 

<^ s'” > 3 N 

A v * ^ 


cS> ^ . 

«& s 5 -a ^ 

0 ’ v ■" a u v, <A ^ 

r\ v . 0 N G /> <£* . v 

*o c % .a~ X 

" ^ * 

“" V- V? 


v Y'g'ghrdggb^ ~ 

Sg? A/>_ 3 w|f \\\^ * c 

■ <> ^AfVV «y 

■\, < 0 . k 4 ■<■' 


r^>* \ 

.A 


o o 


>* 



^ V < A W //. AV"- 3 -^, WV, co 

^•''^ V°°‘/c 0 

-y ^ G => 

* 









* * ' 1 ” > V s - • 4 ,V * - • , “V * 7l 1 A 

* ' '• v * -Waa ^ / 

z <** ^ 

# v A, 


= %4 

: a v \ °J 

* 




^ a * 



^ S 



^ V 

' 0 * fS^» ^ -u 

r \ : C3T > V V " 

O y c .*> v 

' * 0 


* <A 



,0 o. 


\ V 'Vv 


* V \ 0 ’ O <7 0 Q 

0 > , S S ^ r /y & V * " ^ / 

^ V* ^ ^ ^ >4 

* %/ - 

^ ^ Z 

o A V (/>. 

A V f -^ 

C< ‘V ^ 



tP <<£ 

4 % 


y 0 * \ 



*' a 0 j C o r 

,0 V 4 '“ r ^ A- 

- \P 



0 M 



,*o 


^ A 





<P Hr — — v- 

i "0 y n . ^ /« 

v i »4 h+ ° * k <y o 
o. r 0 v c 





^ *^V A ^ 

<1 ^ r 

* x 0 o, 

>y A y<> / 

^ ^ V — s> > 

r^* A a 

A * 0 j 9 ' , „ ^ ' * .0 M 0 0 

A° V c b V ^ " ft 0 ^ 

* :Mjk\ ^ 

O 





v> 



-V 



'o o' k c 1 

° G * , 

tb* = „H •<> ' 









































I z l/A 

|b = X 



& •%. ^ 
f <>* ** - 

0 \V r <- * a I \ * S \' J » „ V \V 

> <. S 9 * ; ^ 17 0 M 0 \V 

v\lo>J* C> V ***«/- > 

‘ ^v> aV * rHY'W A,"' ^ c 

x> *y «, A \V£§y/72, © 


\\’ 



</> ^ 

£ % 



' A 




y .. * 4' 

Sr 

^ X/ / S v 

w N c *A / * * s \ 

C * <**> 

<* ^ I'X ' 

' ^ ^ * 


c^' 

> >t 



V 1 H A 


* '\ '« ^ 

.,V'V/"* %'*•*'/.. 

\ V / -*k^ % ° A 

A v - ’bo' . 

* <* 

l ” 's , . , \>^V .. 

*■ ■«* % a. x ■* /s©v. ** 

% %* » A®!® ' "<^ *• 




<> V 


,s* •%. 



</> 

Kr\ ° 

* * A ' ° * X * T^ „ •', 

o°\.^^ 

, ’°0 i A ^ V 1 

f^ ' 7 b. *,/' 



s 


f 


* -s 

W 3 



& * 4. qV 

s s . \ ^ 0 f x Xo 

A v 1 » * c 0 


> < 


N 


•’ * % .MA'V 

V * 0 r > 0 > s 

& * - vX r 

§ 1 % : ^ ^ 

b *- , z 




.0 o 





^ \“.W; / , ^ 

'' ** s '^ x - z b ' ‘ x b 
•*•■ v w 


AW\ 


< 



























